TABLE OF CONTENTS:
A calorie is a unit of energy. Historically, scientists defined “calorie” to mean a unit of energy or heat that could come from a variety of sources, such as coal or gas. A calorie in nutrition is actually 1,000 of these small calories. Some researchers use the term kilocalories to refer to the nutritional unit of 1,000 small calories. What Americans see on food labels are actually kilocalories, or kilojoules in most other countries. One medium-size apple contains 95 calories, it actually contains 95 kilocalories.
We derive the energy our bodies need from food. In a nutritional sense, all types of foods, whether they are from plant or animal sources, contain calories. Protein, fat and carbohydrates all contain calories.
- 1 gram of protein has 4 calories.
- 1 gram of carbohydrates has 4 calories.
- 1 gram of alcohol has 7 calories. Add on more for sugars.
- 1 gram of fat has 9 calories.
Caloric density refers to the number of calories contained in a certain amount of food, usually per serving or per gram. Foods with higher amounts of fats like animal products or nuts, for example, have a much higher concentration, or density, of calories than leafy greens or broccoli. At a fundamental level, calories as a measurement and units of energy, are calories, but it is much more complicated than that in the nutritional realm.
All calories from foods are not equal. How you burn off calories, whether it is exercising or sleeping, is the same however calories you eat are NOT the same. Calories which come from very processed foods like sugary beverages or refined flour products are absorbed very quickly. Calories from more complex, whole foods are taken up in a much different way.
As an example, let’s compare 160 calories of almonds and 160 calories of soda, about 1 can of Coke. Because of the fiber in almonds, the food does not get broken down, digested and absorbed as quickly. The corresponding blood sugar rise is going to be much lower and for much longer. The triggered insulin secretion from the pancreas is much slower and lower, there is a lower spike and a much less dramatic drop in blood sugar afterwards. A soda on the other hand has no fiber. It gets absorbed almost immediately and goes straight to the liver where the liver gets a huge sugar rush. In addition to the immediate rise in insulin and subsequent crash in blood sugar levels afterwards and the high exposure of the liver to the sugar leads to production of fat.
The sugar industry spins the “calories are equal” myth by promoting the importance of exercise. This issue is dealt with more in my “Exercise” section but as the saying goes, “You can’t out-exercise your mouth”. It takes over an hour of bike riding for a kid to burn off the calories from 1 can of soda. It takes over an hour of swimming to burn off the calories consumed in 1 average cookie. Exercise is important, but the issue IS the food.
How many calories a person needs in a day depends on the individual’s activity level and resting metabolic rate. The National Institutes of Health (NIH) provides general guidelines of calorie requirements for various ages and activity levels. A middle-age moderately active female should consume 2,000 calories per day. A middle-age moderately active male should consume 2,400 to 2,600 calories per day.
Foods that are considered high-calorie, or calorically dense, have a high amount of calories relative to their serving size. High calorie foods include meat, fish, dairy, eggs, oils, butter, fats, fried foods and many processed foods. Some fruits and vegetables are also calorie-dense. These include things like avocado, coconut, nuts and seeds. While high-calorie foods are often associated with junk food, some are high in nutrients, as well. Some examples of calorie amounts in meats include (per serving):
- Chicken breast – 344
- Pork – 363
- Salmon – 367
- Turkey breast – 1166
- Beef brisket – 4308
- Duck – 2137
- Beef brisket – 4308
Healthy foods that are high in calories include avocados (227 calories each), quinoa (222 calories per cup), nuts (828 calories per cup of peanuts), olive oil (119 calories per tablespoon), whole grains, and, in moderation, dark chocolate (648 calories per bar). Although these foods are calorically-dense, they are significantly healthier than calorically-dense animal and processed foods because of all the other healthy things that come along with them like fiber (not found in animal products), minerals and vitamins (also found in smaller amounts in animal products).
Foods that are considered low-calorie have a low amount of calories relative to their serving size. Most fruits and especially vegetables are usually relatively low in calories. For example, 2 cups of shredded romaine lettuce or spinach have 16 calories, a large stalk of celery has 10 calories, 1 large ear of corn has 123 calories, 1 cup of broccoli has 15 calories and an orange has 70 calories.
Empty calories contain few to no nutrients. They often come from added sugars and solid fats like butter, shortening and fats found in some meats. They can occur naturally but are often added to foods. Many typical American foods have a lot of empty calories. Examples include ice cream, sodas, cheese, pizza and processed meats like hot dogs and sausages.
Calories from animal products vs plants. Animal foods are made up of cells which have a membrane and are easily broken down by our digestive system. The calories are maximally extracted and absorbed. Plants have cell walls which are much harder for the digestive system to break down. So, not only is more energy required to digest plants, fewer calories from plants are absorbed. However, the more processed the food, the more the cell walls are broken down and the more calories, fat… can be absorbed. A good example are peanuts. Actually a legume an not a nut, the calories absorbed from an equal amount of peanuts is much lower than what is taken up by consuming peanut butter. The same is true of all nut butters. Most nut butters are also roasted and more carcinogens and inflammatory molecules are produced.
CALORIE DENSITY and NUTRIENT DENSITY
Calorie density refers to the number of calories in a given weight of food. Usually expressed as calories per pound, it can range from as low as 50, for something like watercress, to 4,010 for olive oil. As a general rule of thumb, whole fruits and vegetables have a very low caloric density and you can eat a lot of them without packing on the calories whereas processed foods are in the middle and meat, dairy and oils are very high. Here are a few examples.
- Watercress 50
- Broccoli 150
- Bananas 400
- Brown rice 560
- Black beans 600
- Avocados 730
- Bread 1,100
- Almonds 2,630
- Steak 730
- Chicken 790
- Salmon 830
- Oreos 2,140
- Olive Oil 4,010
As you can see, there are some plant foods, like nuts and avocados which can also be very calorie dense. One simple way of looking at a food and measuring up calories has to do with how full it makes you feel. If you have to eat a lot of something to fill you up, if it is very calorie dense, it is easy to go overboard on the calories. Here is a direct comparison between some equally caloric foods:
- 3.5 tablespoons of olive oil vs 1 serving of sweet potato and squash soup (420 calories)
- 2 Oreo cookies vs 2 cups of cubed cantaloupe (110 cal)
- 3 tablespoons of peanut butter vs 1 large baked potato (110 cal)
- ½ cup dried apricots vs 9 whole apricots (150 cal)
In each case, the second option has a lot more fiber, water content and retained nutrients and you will fill up on them faster. With the first item in each list, it is easy to overeat and go way over your caloric needs.
Nutrient density refers to the amount of nutrition in an equal amount of a specific food. There are a number of scales listing foods based on their nutritional value. Fats and proteins are considered “nutrients” however it is very easy to go way over on these amounts. In fact the average American consumes at least twice as much protein as he or she even needs. Fat is even worse. Plants overall contain the fewest of these and contain the highest density of vitamins minerals and are the only source of fiber. In general, plants are very nutrient dense and meat, fish, dairy and eggs are much poorer sources of nutrition overall and come loaded with all kinds of added bonuses like chemicals, drugs and hormones.
Considering that we have narrowed the variety of crops we grow to eat and have essentially destroyed the nutritional value of the soil and have bred the nutrition out of them (for example apples contain at least 15x less magnesium than ones grown 50 years ago), eating as many nutrient rich plant foods is even more important.
The graph below compares what we ate and the nutrient value of food in 1900 vs 2000. We did not have nutritional information on food back then but the estimates are that overall, food is about 50% less nutritious than it used to be.
NUTRITION BASICS and PHYTONUTRIENTS
Nutrients in foods are divided into 3 categories: Macronutrients, Micronutrients and Phytonutrients.
The term “vitamine” was coined in 1912 by Polish scientist Cashmir Funk who named the special nutritional parts of food after “vita,” meaning life, and “amine” from compounds found in the thiamine he isolated from rice husks. However, the concept of nutritional components was first mentioned in 1905, when Englishman William Fletcher realized that removal of special factors from food would lead to diseases, in his case specifically Beriberi which he associated with rice which lost its thiamine content when processed.
In 1906, English biochemist Sir Frederick Gowland Hopkins also found that certain food factors (proteins, carbohydrates, fats, and minerals) were important to growth in the human body.
In 1924 iodine was first added to salt on a voluntary basis in an attempt to address the prevalent health problem of goiter in the United States. This initial fortification effort was followed in 1933 by the fortification of milk with vitamin D. 1940 the Committee on Food and Nutrition (now the Food and Nutrition Board [FNB]) recommended the addition of thiamine, niacin, riboflavin, and iron to flour.
In 2000, we started identifying phytochemicals in plants along with their myriad of benefits.
Although all these discoveries and understanding of the function of these vitamins, minerals and phytonutrients is important, keeping in mind that they do not function in isolation is equally important. It’s the “symphony” of all these components that brings about good nutrition and health, not isolating and taking concentrated forms of them. Around the time that we started fortifying foods with vitamins (after we stripped away their nutrients by processing them to begin with), cancer rates started to rise and continued to do so until recent years when they started to plateau. Vascular disease also started to rise sharply. In 1900, only 2% of Americans suffered heart attacks or strokes. As of 2007, 40% of Americans suffer heart attacks and 11% have strokes. In addition, obesity rates have slowly increased since 1900 with rates making a sharp increase in the last 30 years. Clearly, our isolation of and obsession with proteins, fats, carbs, vitamins and minerals has not served our health well.
These consist of the big 3 Protein, Fat and Carbohydrates. All the calories in food come from these 3 components.
PROTEIN. Formed by chains of Amino Acids (AA), these compounds are found in all foods, both animal and plant. Although we think of protein as the building blocks of all components in our bodies, it’s actually the individual AAs which make up the proteins which are the actual blocks. Different types of proteins have different proportions of AAs. Some of their functions include:
- Tissue structure (part of organ tissues, muscle, hair, skin, nails, bones, tendons, ligaments and blood plasma)
- Part of cell plasma membranes
- Involved in metabolic, transport, and hormone systems
- Make up enzymes that regulate metabolism
- Involved in acid/base balance to maintain a neutral environment in our bodies
- Stimulate insulin production.
There are 22 AAs, 20 standard ones and 2 atypical ones. In mammals, we really only deal with 20, 9 of which are “essential”, named as such because our bodies cannot make them and 11 non-essential which we can make ourselves. A “complete” protein source is one which has a full complement of both essential and non-essential AAs. Most foods contain all the amino acids in varying proportions however a “complete” protein has adequate levels of all of the proteins. When we consume a protein, we break them down into their individual AAs, absorb them and then re-assemble them into whatever we need. The key difference between animal and vegetable protein is in their amino acid profiles and the rate at which our bodies can absorb amino acids and put them to use. Because animal protein is more similar to protein found in the human body, it is absorbed faster and used up more rapidly than those found in plants however they also contain a greater proportion of sulfur containing AAs such as cystein, methionine and leucine which are more acidifying in the body and we have to work harder to process and neutralize them. The sulfur in these AAs bind with water in the body forming sulfuric acid which leads to more acidic blood. The main way we neutralize this acidity is by using calcium as a buffer. This calcium comes from our muscles and bones. The calcium from muscle is more easily accessible in the short term but day after day and month after month of eating meat, our bones become a greater source and explains why the more animal products you eat, the greater the risk of developing osteoporosis. It also explains why meat-eating athletes have more muscle cramps and recover more slowly from workouts than plant-based athletes. The constant calcium removal from muscle in meat-eaters also explains the greater rate of sarcopenia (muscle loss) in older people who have eaten meat their whole lives. Animal protein is also much more taxing on the kidneys which filter out our blood. Some people argue that animal proteins are more complete than those derived from plants but this is simply not true. People need between 50-130 grams of protein a day depending on how active you are. Keep in mind that our bodies can only process about 25 grams at a time so over-consuming them is not a good idea and stresses the body too much. NOTE: 1 gram of protein has 4 calories.
ESSENTIAL AMINO ACIDS and the plants that contain them:
- Isoleucine: watercress, chard, sunflower seeds, spinach, kidney beans
- Leucine: alfalfa seeds, kidney beans, watercress, sunflower seed
- Lysine: watercress, walnuts, peas, lentils, almonds, chickpeas
- Methionine and Cysteine: sesame seeds, seaweed, spirulina, Brazil nuts, oats
- Phenylalanine and Tyrosine: sesame seeds, kidney beans, spinach,peanuts
- Threonine: watercress, spinach, sesame seeds, sunflower seeds, kidney beans
- Tryptophan: spinach, turnip greens, broccoli rabe, asparagus, oat bran, kidney beans, watercress
- Valine: mushrooms, snow peas, kidney beans, sunflower seeds, sesame seeds
- Histidine: apples, beets, carrots, celery, cucumber, spinach
FAT. Fats are just one type of lipid, a category of molecule unable to mix well with water. A fat molecule consists of two kinds of parts: a glycerol backbone and three fatty acid tails. Fat molecules are also called triacylglycerols, or, in bloodwork done by your doctor, triglycerides. Glycerol is a small organic molecule with three hydroxyl (OH) groups, while a fatty acid consists of a long hydrocarbon chain attached to a carboxyl group. A typical fatty acid contains 12–18 carbons, though some may have as few as 4 or as many as 36. These oily compounds serve various functions and are, like proteins, are also found in all animal and plant foods. Some of their functions include:
- Energy reserve source.
- Protection of vital organs.
- Insulation of nerves fibers and cells as well as under the skin.
- Transport fat soluble vitamins.
- Cell wall component and support.
- Hormone production.
There are a few different types of fats, all of which have 9 calories per gram:
- Saturated fat. Saturated means that all molecules of fat are “saturated” with hydrogen atoms. This is the worst kind of fat. It is usually solid at room temperature. The majority of saturated fat comes from animal products such as beef, lamb, pork, poultry and dairy products. All of these foods also contain dietary cholesterol. Foods from plants that contain saturated fat include coconut, coconut oil, palm oil and palm kernel oil (often called tropical oils) and cocoa butter.
- Unsaturated fat. These molecules are not completely saturated with hydrogen atoms. There are 2 forms: Polyunsaturated which have many sites are free of hydrogen atoms (oily fish like sardines, mackerel, trout, salmon, and herring, vegetable oils, nuts and seeds) and monounsaturated which have only one site is free (olives, olive oil, nuts, peanut butter, and avocado). Both polyunsaturated and monounsaturated fats may help improve your blood cholesterol when used in place of saturated and trans fats but this is deceptive. Replacing a “bad” fat with a “less bad” fat is not a good approach. The well-publicized Omega 3 and 6 fats are polyunsaturated however, there are other omegas to consider. Omega 7s are also known as palmitoleic acids. These monounsaturated fatty acids are lipokines, hormone-like molecules which control what other fats are doing in your body. They ensure optimal energy use and storage and as a result, impact significantly on fat metabolism. Good sources of these fats include avocados, macadamia nuts and cold water fish like salmon and sardines. If you choose to consume fish, make sure they are as high quality as you can get. Omega 9s are known as oleic acids. This is the most common type of monounsaturated fat in a healthy diet. It is one of the main types of oils in olive oil. Other sources include avocados, macadamias and almonds as well as sunflower seeds. Omega-3 are polyunsaturated fats and they have numerous benefits, not the least of which is brain health and lowering inflammation. The 3 main forms are DHA (docosahexaenoic acid), EPA (eicosapentaenoic acid) and ALA (alpha-linoleic acid). The predominant form in animal products like fish is DHA and EPA and the main form in plants is ALA. Although ALA is much less potent than the other two, it can be converted into the other two in the body. The process however is not very efficient with some reports suggesting that only 5% of ALA getting converted into EPA and 1% getting converted into DHA. Great plant sources of omega-3s include flax, chia and hemp seeds, walnuts, kale and purslane. If omega-3 is anti-inflammatory, omega-6, also a polyunsaturated fatty acid, is pro-inflammatory. Some inflammation is necessary but there is an important balance between omega-3 and omega-6 is the key. It used to be 1:1-1:3 when we ate mostly whole food but today’s factory produced processed food, which leads to a ratio closer to 1:20. In some segments of the population the ratio can be as high as 1:50! They are mostly found in plant oils. Two forms of omega-6 which decrease inflammation are gamma-linolenic acid (GLA) and conjugated linoleic acid (CLA).
- Trans Fat. Trans fats (or trans fatty acids) are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid. Another name for trans fats is “partially hydrogenated oils.” Trans fats are found in many fried foods and baked goods such as pastries, pizza dough, pie crust, cookies and crackers. Trans fats raise your bad (LDL) cholesterol levels and lower your good (HDL) cholesterol levels. These changes are associated with a higher risk of heart disease. The US is one of only 4 countries which have outright banned trans fats. Denmark, Switzerland and Sweden being the other three. Many other countries have strict controls but not banns. That having been said, there are many other food additives allowed in the US which convert into trans fats so they are still getting in via processed foods. There is more below about how trans fats can still get into our diet. Although they do occur naturally in some animal products like meat and fish, it accounts for only 1-10% of the fat content.
CARBOHYDRATES. These are the sugars, starches and fibers found in fruits, grains, vegetables and dairy products. They are not found in any meat products. They play a vital role in the body. They fuel us during high exercise. They also fuel for the Central Nervous System (your brain!) which uses 75% of the sugars we consume despite being a small organ comparatively speaking.
In a similar way that protein is made up of strings of amino acids, carbohydrates are made up of chains of monosaccharides. The most abundant monosaccharides are glucose and fructose. Sucrose, which makes up table sugar, and lactose, the main sugar in dairy products, is mostly made up of glucose. In the case of lactose, the other monosaccharide is galactose, implicated in ovarian diseases like cancer. Glucose is stored glycogen, sparing protein (to preserve muscle mass during exercise). Also like protein, they have 4 calories per gram. Not all carbohydrates are the same. The more processed they are (think flower, pastries, rolled vs steel cut oats, pastas…) the faster they are broken down and the faster they are absorbed in the body. This accelerated process leads to spike in sugar levels in the body creating all kinds of problems like insulin spikes and hormone dysregulation. The more “whole” a carbohydrate is, the better.
ALL macronutrients contain calories:
- 1 gram of protein has 4 calories.
- 1 gram of carbohydrates has 4 calories.
- 1 gram of fat has 9 calories.
On average, a person uses about 10% of their daily energy expenditure digesting and absorbing food, but this percentage changes depending on the type of food you eat. This is called the “thermal effect of food”. The amount of energy required to digest the 3 man macronutrients is also quite different. The amount of energy required to digest those macronutrients is also significantly different.
- Protein – 20-30% of the calories in protein is used to digest it. Proteins are complex with coiled strings of amino acids which need to be separated and this requires a lot of energy. Americans consume so much protein though that we still get way more than our bodies can utilize and this is problematic.
- Carbohydrates – 5-10% of the contained calories are used to digest it.
- Fat – 0-3%. Much less and this is part of the problem. Fat is easy to digest so most of it gets processed.
- Fiber takes a lot of energy to break down and in fact, much if it never actually gets broken down and just adds to stool bulk. Celery is a classic example. You burn more calories digesting celery than the celery actually contains.
Oxidative Priority. Macronutrients are broken down in order based on their complexity and nutrient value which is based significantly on storage capacity. For example, alcohol (not really a macronutrient but a frequent and important component of meals for most people) has no storage capacity, contains no valuable calories, just “empty calories” and is first to be metabolized by the body, primarily the liver. Fat on the other had had unlimited storage capacity so it is the last to be dealt with by the body. That’s why we store so much fat!
Order of priority:
- Alcohol. NO storage capacity. Alcohol actually has 7 calories per gram (1 shot).
- Protein. Very limited storage capacity (300-500 calories max) mostly in muscle and some in the blood.
- Carbohydrates. We can store about 2000 calories of carbs as glycogen. There is also a difference between simple carbs like pastries, flower products or sugar, which get metabolized immediately and processed by the liver often into fat, and complex carbohydrates like whole fruits and vegetables which are much more slowly broken down, used as fuel and stored as glycogen in the muscles.
- Fats. Last to get metabolized, we can store unlimited amounts of fat, an that is evident by the fact that 70% of the US population is at least over weight and 40% are frankly obese.
This partly explains why we are so fat and unhealthy as a society. The foods we eat are often full of all of those macronutrients, often with a disproportionate amount of unhealthy foods which are prioritized or have a lot of storage capacity (ie alcohol, protein and fat). We have de-prioritized the healthy carbohydrates like whole fruits and vegetables which should NOT be lumped in with the hyper processed carbs like breads, crackers and snack foods.
WATER and FIBER. I would put these in the macronutrient category but to keep things simpler, the big three above are easier to understand.
37 Billion billion chemical reactions occur in our bodies every second. Each of these reactions are impacted by co-factors, which consist of vitamins and minerals. 1/3rd of our DNA codes for enzymes which help with those reactions as well.
Micronutrients are small compounds needed in minimum amounts to enable the body to produce enzymes, hormones and other substances essential for healthy growth and development. They include vitamins and minerals and the do not have any calories. Vitamins are necessary for energy production, immune function, blood clotting and other functions. Meanwhile, minerals play an important role in growth, bone health, fluid balance and several other processes. Vitamins and minerals differ in basic ways. Vitamins are organic and can be broken down by heat, air, or acid. Minerals are inorganic and hold on to their chemical structure. The minerals in soil and water easily find their way into your body through the plants, fish, animals, and fluids you consume. It’s more difficult to shuttle vitamins from food and other sources into your body because cooking, storage, and simple exposure to air can inactivate these more fragile compounds.
- VITAMINS. There are 14 vitamins. Some are fat soluble and some are water soluble. They do break down over time which is why frozen foods are sometimes more nutritious than those which have traveled half way around the world or even across the country.
- The fat-soluble vitamins, A, D, E, and K, are stored in the body for long periods of time and generally pose a greater risk for toxicity when consumed in excess than water-soluble vitamins. Eating a normal, well-balanced diet will not lead to toxicity in otherwise healthy individuals. One important note about these is that the more weight you have (ie more fat cells in your body), the greater the risk of deficiencies in these vitamins because the fat removes these vitamins from circulation.
- Water-soluble vitamins are those that dissolve in water upon entering the body. Because of this, your body cannot store excess amounts of water-soluble vitamins for later use. There are a total of nine water-soluble vitamins: the B vitamins which include folate, thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B6 and vitamin B12, and vitamin C. Vitamin C is interesting in that only Humans and Guinea Pigs cannot make vitamin C, which most animals can. We must get it from the foods we eat.
- MINERALS. There are 25 minerals. Unlike vitamins, they do not break down over time. These are divided into macrominerals (we need more of these) and trace minerals.
- The macromineral group is made up of calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur.
- Trace minerals includes iron, manganese, copper, iodine, zinc, cobalt, fluoride, and selenium.
- WATER. This may sound odd, but water is a crucial nutrient in many metabolic processes, donating hydrogen and oxygen (H2O), and facilitating many reactions. In our 20’s, we are approximately composed 70% by water. This drops to 50% by our 60’s. The fact is that 80% of Americans are walking around dehydrated. In addition, people start taking various medications like diuretics for blood pressure for various conditions which add to “insensible water loss”. Just breathing and perspiring while you sleep leads to enough eater loss to wake up in a relatively dehydrated state every morning. In addition, fruits and vegetables are very high in water content, as much as 95% for things like zucchini, greens, mushrooms and watermelons. Meat is at most 75% water and this is often water which is injected into the tissue to plump it up. Refined carbs are however worse. cornflakes contain 4% water and a whole wheat bagel has 34% water.
- FIBER. This is such an important micro-nutrient that it gets its own section. Click here to learn more about fiber. Fiber, which you only get from plants, none from any animal products, do not just feed us, they feed the trillions of bacteria in our intestinal tract, keeping them healthy and providing for a healthy microbiome. Fiber doesn’t just provide nourishment for our healthy bacteria and bulk to our stool. It also binds many vitamins, minerals and phytonutrients (plant nutrients). Up to 80% of them. The healthy bacteria breakdown the fiber and release those healthful compounds. When you juice fruits and vegetables, you remove the fiber and in doing so, remove almost 80% of the phytonutrients. Blending is better than juicing since the fiber is not removed but you can consume a lot of calories quickly in a liquid form. EAT YOUR PLANTS WHOLE.
- ANTIOXIDANTS. These are compounds found in brightly-colored plant foods. Although they do occur in some animal products, plants contain on average 64x more antioxidants. These compounds mitigate the damage which occurs to tissue when free radicals, formed by various normal and inflammatory processes which cause oxidation, try to grab an electron to “stabilize” themselves. Antioxidants act as electron “donors”, stabilizing free radicals.
- PHYTOCHEMICALS. See below.
PHYTONUTRIENTS and POLYPHENOLS
Also technically a micronutrient, this last, underappreciated category was discovered in the late 1990’s. Plant foods contain thousands of natural protective chemicals called phytonutrients. “Phyto” refers to the Greek word for plant. These compounds help protect plants from germs, fungi, bugs, bad weather, overexposure to the sun (XRays) and other threats. Although phytonutrients aren’t essential for keeping humans alive like vitamins and minerals are, their importance in maintaining good health is becoming increasingly clear. The protective benefits they provide the plants DO transfer over and protect humans as well. When you consume phytonutrients, they help prevent disease and keep your body working properly in the same way they protect the plants they come from. This phenomenon of transferred protection is called xenohormesis. There is an old saying, “That which does not kill you, makes you stronger'”. There is truth in this. Examples include:
- The purple color of grapes and eggplant protects the fruits and vegetables from the sun.
- The bitter taste in greens is to discourage insects from eating them. These compounds increase when they are attacked. The “bitterer”, the healthier.
- Orange growers know that if they bang a nail into the trunk of an orange tree a day or 2 before harvest, the oranges are plumper and tastier, a reaction to the “threat” and injury from the nail.
- Apples that have been bitten by a grub or other insect have higher concentrations of vitamins than those which are grown conventionally and are sprayed with chemicals.
Small amounts of stress cause our bodies to protect and re-build themselves. This is what happens every time you exercise. Microtears in muscle get re-built and that’s how muscles grow. The same goes for phytonutrients. When exposed to stress, plants generate these compounds and, in many cases, the protective benefit of these compounds is transmitted to us when we consume them. This is also why plants which grow in the wild generate more protective than those grown in green houses, protected from the elements. In some cases by 10x.
Polyphenols are known to turn off NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), a protein complex that controls transcription and expression of over 400 genes involved in inflammation and cell survival. It is found in almost all animal cell types and is involved in cellular responses to stimuli such as stress, cytokines, free radicals, heavy metals, ultraviolet irradiation, oxidized LDL, and bacteria or viruses. NF-κB plays a key role in regulating the immune response to infection. Incorrect regulation of NF-κB has been linked to cancer, inflammatory and autoimmune diseases, septic shock, viral infection, and improper immune development. NF-κB has also been implicated in processes of synaptic plasticity and memory.
Research reveals that phytochemicals have significant anti-carcinogenic powers by:
- Providing antioxidant activity and scavenging harmful, cancer causing free radicals.
- Preventing DNA damage.
- Repairing broken DNA.
- Destroying harmful cells in our body.
- Tempering the growth rate of cancer cells.
- Inhibiting angiogenesis (growth of new blood vessels to supply tumor cells).
- Stimulating the immune system.
- Regulating hormone metabolism.
- Improving insulin sensitivity and blood sugar control.
- Reducing inflammation.
- Supplying antibacterial and antiviral effects.
More than 25,000 phytonutrients have been identified in plant foods. We still don’t know much about them. A typical tomato has over 10,000. Here are a few common ones we do know something about:
- Carotenoids. More than 600 different carotenoids provide the yellow, orange, and red colors in fruits and vegetables. They act as antioxidants which means they tackle harmful free radicals that damage tissues throughout your body. The types of carotenoids that may have other health benefits include:
Alpha-carotene, beta-carotene, and beta-cryptoxanthin. Your body can convert all of these to vitamin A which helps keep your immune system working properly and is needed for eye health. Yellow and orange foods like pumpkins and carrots are good sources of alpha- and beta-carotene.
Lycopene. This gives red or pink color to: tomatoes, watermelon and pink grapefruit It has been linked to a lower risk of prostate cancer.
Lutein and zeaxanthin. These may help protect you from cataracts and age-related macular degeneration, which are two types of eye problems. Good sources of these phytonutrients are greens such as spinach, kale and collards.
- Carotenoids. More than 600 different carotenoids provide the yellow, orange, and red colors in fruits and vegetables. They act as antioxidants which means they tackle harmful free radicals that damage tissues throughout your body. The types of carotenoids that may have other health benefits include:
- Ellagic Acid and Ellagitannins. These are found in a number of berries and other plant foods, especially: strawberries, raspberries, pomegranates and walnuts. Ellagic acid may help protect against cancer several different ways. For, it may slow the growth of cancer cells. It may also help your liver neutralize cancer-causing chemicals in your system. Urolithn A, a compound converted from ellagic acid by hut-friendly bacteria, was shown to induce mitophagy, which is a selective recycling of mitochondria by autophagy, a process that cleans defective mitochondria following damage or stress, and tends to become less efficient during aging.
- Flavonoids. A large number of phytonutrients fall into the flavonoid category. They are found in a variety of plant foods and include:
Catechins. Green tea is an especially good source of catechins. The drink may help prevent certain types of cancer.
Hesperidin. Found in citrus fruits, this flavonoid works as an antioxidant reducing inflammation in the body to help prevent chronic disease.
Flavonols. Quercetin is a well-studied type of flavonol. It is found in: apples, berries, kale and onions. It might help reduce people’s risk of asthma, certain types of cancer, and coronary heart disease.
- Flavonoids. A large number of phytonutrients fall into the flavonoid category. They are found in a variety of plant foods and include:
- Resveratrol. This is found in: grapes, purple grape juice and red wine. It acts as an antioxidant and anti-inflammatory. Some research suggests that resveratrol might play a role in reducing the risk of heart disease and certain cancers. Some animal studies have shown that resveratrol extends longevity but more human studies are needed to establish a clear relationship.
- Glucosinolates. Glucosinolates are found in cruciferous vegetables including brussels sprouts, cabbage, kale and broccoli. They give these vegetables their sharp odor and flavor. The glucosinolates turn into other chemicals during the cooking process and while you digest these foods. These chemicals may help hold in check the development and growth of cancer. Glucosinolates which are converted into isothiocyanate, a potent anti cancer compound. It is so potent that Johns Hopkins University makes a pill with concentrated isothiocyanates. The pill is dubbed the ‘Broccoli” pill since broccoli contains high amounts of this compound.
- Phytoestrogens. There is a lot of confusion about these compounds because of concern about estrogen and cancer, especially breast cancer. Although similar in structure, the plant phytoestrogens do not have the same effects as the estrogen in humans or ingested from animals and dairy products. They actually block the effects of animal, and human, estrogens and are protective. Soy foods contain isoflavones, a type of phytoestrogen. Soy foods are linked to lower risk of breast and endometrial cancer in women and prostate cancer in men. It’s also also linked with a lower risk of bone loss in women. Your body converts lignans, another type of phytonutrient, into chemicals with some estrogen-like effects. Two especially good sources of lignans are flax and sesame seeds. Other sources of healthful phytoestrogens include: oats, barley, beans and lentils, apples, carrots, sesame seeds, hops (used to make beer) and many other fruits and vegetables.Phytoestrogens are also found in clover, sweet potato and soy. Sheep feeding on clover became infertile because of it’s high concentration of the phytoestrogen formonenin. The phytoestrogen disogenin in the Mexican yam was used to synthesize the first contraceptive pill in 1951.
- Phenolic acids. This group accounts for around 30% of all polyphenols. Examples include stilbenes and lignans, which are mostly found in fruits, vegetables, whole grains, and seeds.
- Polyphenolic amides. This category includes capsaicinoids in chili peppers and avenanthramides in oats.
Plant compounds known to block carcinogenic activity include:
- Sulforaphane – broccoli and kale
- Indole 3 Carbinol – broccoli and kale
- Genistein – soy
- Diallyl Sulfide – garlic and onions
- Ellagic Acid – berries and walnuts
- Curcumin – turmeric
- Epigllocatechtin (EGCG) – green tea
- Resveratrol – green grapes
- Omega 3 Fatty Acids – flax seeds and avocado
- Procyanidins – berries
- Lycopene – tomatoes
- Anthocyanidins – apples
- Limonene – lemons and oranges
Oxidation is any chemical reaction that involves the moving of electrons. Specifically, it means the substance that gives away electrons is oxidized. Normally, this is a reaction between oxygen and a substance such as iron. When iron reacts with oxygen it forms rust. This process involves iron losing some electrons (being reduced) and the oxygen gaining some electrons (being oxidized).
Oxidation is the opposite of reduction. A reduction-reaction always comes together with an oxidation-reaction. Oxidation and reduction together are called redox (reduction and oxidation). Oxygen, however, does not have to be present in a reaction for it to be a redox-reaction.
Oxidation is the loss of electrons. Reduction is the gain of electrons.
In terms of oxygen transfer, oxidation may be defined as the chemical process in which a substance gains oxygen or loses electrons and hydrogen. When one of the reactants is oxygen, then oxidation is the gain of oxygen. Reduction is a loss of oxygen.
Oxidative stress is an imbalance between free radicals and antioxidants in your body. Free radicals are oxygen-containing molecules with an uneven number of electrons. The uneven number allows them to easily react with other molecules. Free radicals can cause large chain chemical reactions in your body because they react so easily with other molecules. These reactions are called oxidation. They can be beneficial or harmful.
Antioxidants are molecules that can donate an electron to a free radical without making themselves unstable. This causes the free radical to stabilize and become less reactive.
ANTIOXIDANTS – Explained in Simple Terms
You may have heard a lot of talk about antioxidants, however, few people know what they are or how they work.
In a nutshell, antioxidants are molecules that neutralize free radicals in your body.
What are free radicals? Atoms are surrounded by electrons that orbit the atom in layers called shells. Each shell needs to be filled by a set number of electrons. When a shell is full, electrons begin filling the next shell. If an atom has an outer shell that is not full, it may bond with another atom, using its electrons to complete its outer shell. These “incomplete” types of atoms are known as free radicals. Atoms with a full outer shell are stable, but free radicals are unstable and, in an effort to make up the number of electrons in their outer shell, they react quickly with other molecules, degrading them.
Free radicals are constantly being formed in your body. Free radicals do serve important functions that are essential for health. For example, your immune cells use free radicals to fight infections. Chemotherapy for cancer often works by generating free radicals which kill cancer cells. In fact, when taking chemotherapy, patients are often told to stop all vitamins, especially those high in antioxidants. They are even told sometimes to avoid excessive amounts of fruit and vegetables because the antioxidants in them make the chemotherapy less effective!
When free radicals are produced in excess however, tissue and cellular damage occurs. Antioxidants keep free radicals in check. As with everything in life, balance is the key. Your body needs to maintain a certain balance of free radicals and antioxidants. When free radicals outnumber antioxidants, it can lead to a state called oxidative stress which can damage your DNA and other important molecules in your body. Sometimes, it even leads to cell death.
Your body generates its own antioxidant defenses to keep free radicals in check. Antioxidants are also found in food, especially in fruits, vegetables, and other plant-based, whole foods. Although animal products do have antioxidants, plants contain 30x more. Most vitamins, such as vitamins E and C, are effective antioxidants. Antioxidants also act as preservatives and play a crucial role in food production by increasing shelf life.
Several lifestyle, stress, and environmental factors are known to promote excessive free radical formation and oxidative stress, including:
- air pollution
- cigarette smoke
- alcohol intake
- toxins of any kind including chemicals, radiation, even fragrances.
- high blood sugar levels
- high intake of polyunsaturated fatty acids (saturated fat)
- radiation, including excessive sunbathing and medical tests
- bacterial, fungal, or viral infections
- excessive intake of iron, magnesium, copper, or zinc
- too much or too little oxygen in your body. Too little can be the result of lung disease or sleep apnea.
- intense and prolonged exercise, which causes tissue damage
- emotional stress.
- excessive intake of antioxidants, such as vitamins C and E
- antioxidant deficiency (this is very common)
Antioxidants are essential for the survival of all living things. Although your body generates its own antioxidants, such as the cellular antioxidant glutathione, their production diminishes with age and foods become more and more important sources of antioxidants. In addition, antioxidants are used up very quickly. Just the stress of driving home in traffic is enough of a stress to wipe out all the antioxidants in your circulation
Plants and animals, as well as all other forms of life, have their own defenses against free radicals and oxidative damage. Antioxidants are found in all whole foods of plant and animal origin.
Berries, green tea, coffee, and dark chocolate are renowned for being good sources of antioxidants. Coffee is the single biggest source of antioxidants in the Western diet, but this is because the average individual doesn’t eat that many antioxidant-rich foods to begin with but most people guzzle the coffee.
Meat products and fish also contain antioxidants, but to a much lesser extent than fruits and vegetables.
Types of dietary antioxidants. Antioxidants can be categorized as either water or fat soluble. Water-soluble antioxidants perform their actions in the fluid inside and outside cells, whereas fat-soluble ones act primarily in cell membranes because those membranes are made up mostly of fatty acids.
Important dietary antioxidants include:
- Vitamin C. This water-soluble antioxidant is an essential dietary nutrient.
- Vitamin E. This fat-soluble antioxidant plays a critical role in protecting cell membranes against oxidative damage.
- Flavonoids. This group of plant antioxidants has many beneficial health effects.
Many substances that happen to be antioxidants also have other important functions. Notable examples include curcuminoids in turmeric and oleocanthal in extra virgin olive oil. These substances function as antioxidants but also have potent anti-inflammatory activity.
Dietary intake of antioxidants is essential for optimal health, but more is not always better. Excessive intake of isolated antioxidants can have toxic effects and may even promote rather than prevent oxidative damage. Eating plenty of antioxidant-rich whole food is a much better idea. Studies indicate that foods reduce oxidative damage to a greater extent than supplements. For example, one study compared the effects of drinking blood-orange juice and sugar water, both of which contained equal amounts of vitamin C. It found that the juice had significantly greater antioxidant power.
Foods’ compounds work synergistically. Taking just one or two isolated nutrients won’t have the same beneficial effects. Another example is Vitamin E. There are actually 8 different forms of this vitamin in foods but supplements often have only or maybe 2 forms. As a result, absorption of the other forms from food is blocked. In addition, Vitamin E supplements, in high enough doses, have been linked to prostate cancer in men.
The best strategy to ensure adequate antioxidant intake is to follow a diet rich in various vegetables and fruits, alongside other healthy habits. However, low-dose supplements, such as multivitamins, may be beneficial if you are deficient in certain nutrients or unable to follow a healthy diet. One notable example is Vitamin D. Actually a hormone, it is crucial to hormonal and bone health and about 70% of Americans are deficient. It comes primarily from adequate sun exposure since it is made from cholesterol in the skin exposed to UV radiation. Mushrooms and foods fortified with vitamin D are dietary sources but it is often not enough for most people who are deficient.
Antioxidants are substances that reduce oxidative stress by combating free radicals formed by inflammation in the body. We make them and we consume them when we eat plants. One of the one we can make is glutathione and it is one of the most potent antioxidants in the body. It is found in every cell in the human body. In fact, it’s found in every cell of all animals, plants, fungi and even bacteria. Discovered in 1921 by Sir Frederick Gotland Hopkins, it is a simple protein composed of only 3 amino acids: glutamic acid, cysteine and glycine. In comparison, human growth hormone requires 191 amino acids. Our bodies can manufacture those 3 amino acids but as we age, our ability to produce those amino acids decreases and the role of diet increases.
Glutathione is produced by the liver and is found in high concentrations there because of its important role in detoxification. It enhances our immune defenses and protects against DNA damage.
Depletion of 20-30% of our glutathione can impair cellular defense systems and lead to abnormal cell-to-cell communication, and cause various adverse effects including protein breakdown and cell injury. We’ve learned that as little as 5 days of sleep deprivation can impair the production of glutathione by 30%. However, sleep recovery showed restoration of glutathione and antioxidant activity in both liver and heart.
Foods high in glutathione include:
- Spinach (raw)
- Winter squash
- Potatoes with skin
- Beef, poultry and fish have some as well but no more than plants do.
Foods high in the amino acid cysteine:
- Peanuts and peanut butter
- Beef, poultry and fish have more cysteine than fruits and vegetables because they also contain more sulfur containing amino acids but these also acidify the blood, leading to osteoporosis so focus on the plants.
Foods high in glutamic acid include:
- Beans, especially soybeans
- Green tea
- Some fish and cheese
Natural Ways to Increase Your Glutathione Levels
There are a number of reasons why your body’s glutathione level may become depleted, including poor diet, chronic disease, infection and constant stress. Maintaining adequate levels of this antioxidant is incredibly important. Below are 10 of the best ways to increase your glutathione levels naturally.
- Consume Sulfur-Rich Foods. Sulfur is an important mineral that occurs naturally in some plant and protein foods. It’s required for the structure and activity of important proteins and enzymes in the body. Notably, sulfur is required for the synthesis of glutathione. A number of human and animal studies have found that eating sulfur-rich vegetables may reduce oxidative stress by increasing glutathione levels.
Sulfur is found in two amino acids in food: methionine and cysteine. It’s primarily derived from dietary proteins, such as beef, fish and poultry however those sources also acidify the blood, leading to calcium breakdown in our bones. Better sources of sulfur include vegetables such as cruciferous vegetables like broccoli, Brussels sprouts, cauliflower, kale, watercress and mustard greens and allium vegetables, including garlic, shallots and onions, also boost glutathione levels, likely due to their sulfur-containing compounds.
- Increase Your Vitamin C Intake. Vitamin C is a water-soluble vitamin found in a variety of foods, particularly fruits and vegetables. Strawberries, citrus fruits, papayas, kiwis and bell peppers are all examples of foods rich in vitamin C. This vitamin has many functions, including working as an antioxidant to protect cells from oxidative damage. It also maintains the body’s supply of other antioxidants, including glutathione. Vitamin C may help increase glutathione levels by attacking free radicals first, thereby sparing glutathione. Vitamin C helps reprocess glutathione by converting oxidized glutathione back to its active form. Taking vitamin C supplements increases glutathione levels in white blood cells in healthy adults.
- Add Selenium-Rich Foods to Your Diet. Selenium is an essential mineral and a glutathione cofactor, a substance needed for glutathione activity. Some of the best sources of selenium are some meats but it’s better to get selenium from healthier sources like brown rice and Brazil nuts.
- Eat Foods Naturally Rich in Glutathione. The human body produces glutathione, but there are also dietary sources. Spinach, avocados, asparagus and okra are some of the richest dietary sources. However, dietary glutathione is poorly absorbed by the human body. Additionally, cooking and storage conditions can decrease the amount of glutathione found in food. Despite having a lower impact on increasing glutathione levels, glutathione-rich foods may help decrease oxidative stress.
- Milk Thistle. Milk thistle supplements are another way to boost glutathione levels naturally. This herbal supplement is extracted from the milk thistle plant, known as Silybum marianum. It consists of three active compounds, collectively known as silymarin. Silymarin is found in high concentrations in milk thistle extract and is well known for its antioxidant properties. Silymarin has been shown to increase glutathione levels and prevent depletion in both test-tube and rodent studies. It is able to maintain glutathione levels by preventing cell damage.
- Turmeric Extract. Turmeric is a vibrant yellow-orange herb and a popular spice in Indian cuisine. The herb has been used medicinally in India since ancient times. The medicinal properties of turmeric are likely linked to its main component, curcumin which is much more concentrated in the extract form of turmeric, compared to the spice. Numerous animal and test-tube studies have shown that turmeric and curcumin extract have the ability to increase glutathione levels. Curcumin found in turmeric may assist in restoring adequate levels of glutathione and improve the activity of glutathione enzymes.
- Sleep Well. As mentioned above, poos sleep depletes glutathione. A good night’s rest is essential for overall health. Interestingly, long-term lack of sleep can cause oxidative stress and even hormone imbalances.
- Exercise. Regular physical activity has long been recommended by physicians and healthcare providers. It’s no surprise that exercise is good for both your physical and mental health. Recent research shows that exercise is also helpful in maintaining or increasing antioxidant levels, especially glutathione. Completing a combination of both cardio and circuit weight training increases glutathione the most, compared to completing cardio or weight training alone. However, athletes who over-train without maintaining adequate nutrition and rest may be at risk of decreased glutathione production.
- Avoid Drinking Too Much Alcohol. Excessive alcohol causes a lot of inflammation, leading to free radical formation. <any organ systems are affected. While not as well known, lung damage is also an adverse effect of alcoholism. This is likely related to a depletion of glutathione levels in the lungs. The small airways of the lungs require glutathione to function properly. Healthy lungs have up to 1,000x more glutathione than other parts of the body. Depletion of glutathione in the lungs of alcoholics is most likely due to oxidative stress caused by chronic alcohol use. There is an 80–90% decrease in lung glutathione levels in those who regularly consume excessive amounts of alcohol.
GLYCEMIC INDEX AND GLYCEMIC LOAD
The glycemic index (GI) is a measure of the blood glucose-raising potential of the carbohydrate (sugar) content of a food compared to a reference food (pure glucose). Carbohydrate-containing foods can be classified as high (≥70), moderate (56-69) or low-GI (≤55) relative to pure glucose (100). Consumption of high-GI foods cause a sharp increase blood glucose concentration that declines rapidly, whereas consumption of low-GI foods results in a lower blood glucose concentration that declines gradually. Part of the problem with using GI as a guide for eating is that a specific foods GI can be affected by its ripeness and how the food is prepared. A great example are bananas. 98% of the calories from a banana come from carbs. When under ripe, the GI is much lower than when it is ripe since much of the resistant starch (which accounts for 80-90% of the carbs when under ripe) is converted into simpler, more rapidly digestible sugars as it ripens. Roasting foods also increased their GI as the sugars are broken down. Processed, refined foods like white bread or pastries have high a GI because the sugars get absorbed quickly since there is a lot of air which leads to more surface area for enzymes to break things down. Pasta lie spaghetti, especially when it is al dente (meaning a little firm and not overdone) tends to have a much lower GI because it is dense and gets digested and absorbed more slowly.
The glycemic load (GL) is obtained by multiplying the quality of carbohydrate in a given food (GI) by the amount of carbohydrate in a serving of that food. This is a more practical value.
A food with a high GI raises blood sugar more than a food with a medium to low GI but the glycemic index but does not take into account the amount of carbohydrate in a food. So glycemic load is a better indicator of how a carbohydrate food will affect blood sugar. As an example, watermelon has a high GI (72), which is relatively high. However, a typical serving size (1 cup or a 1-inch wedge) only has 5 grams of carbohydrate and its GL is very low (3.6). You would practically have to eat half a watermelon for it to significantly impact on your blood sugar.
Lastly, and most importantly, you have to consider a whole meal and not just individual food items. For example, one slice of white bread has a very high GI (>70) and even worse GL (100) however, if you put hummus on it along with some tomatoes, spinach and broccoli sprouts, the overall nutrition of the bread is improved. I am certainly not condoning eating white bread but the points are 1) consider everything on your plate, good and bad and 2) eat your whole fruits and vegetables and avoid processed foods. In addition, a Snickers candy bar has a GI of 43 (low) and peanut butter has a GI of 33 (even lower) but both have a significant amount of fat along with other potential harmful ingredients.
EAT WHOLE UNPROCESSED FOODS, MOSTLY PLANTS WITHOUT FAT AND YOU DON’T NEED TO WORRY ABOUT GI OR GL!
For a easy place to look up the glycemic index of specific foods, click here.