More than two thousand years ago, the ancient Greek physician Hippocrates advised us how important foods are for our health. Today, medical science continues to substantiate this wise adage. Studies have found that populations whose diets feature significant amounts of certain foods have a significantly lower risk of developing many chronic degenerative diseases including, but not limited to, cardiovascular disease, type II diabetes mellitus, cancer, rheumatoid arthritis, and depression. In fact, five of the top ten causes of death in the United States are associated with the Standard American Diet. An ever-growing body of research has brought both scientists and nutritionists to propose that we can significantly decrease morbidity and mortality, and dramatically improve our chances of living a longer, healthier more vibrant life, simply by eating healthier foods.
So, what distinguishes a health-promoting diet from one that does not support health and vitality? Research shows that diets featuring whole grains, fresh fruits and vegetables, legumes and fish, like in the World's Healthiest Foods, are not only associated with lower risks of diseases, but also promote healthy aging. Furthermore, evidence continues to accumulate that pesticides and other environmental toxins used in the growing and manufacture of conventional, processed foods have a deleterious impact on your health.
In order to fully appreciate how nutrition is vital to your optimal wellness, let's look at some important foods and the key nutrients they contain, and discuss their impact on your health. We will also provide reliable information on the negative impact of additives and pesticides on your health.
Some Key Nutrients in Whole Grains, Fresh Fruits and Vegetables
Research studies show that fresh fruits and vegetables may offer protection against chronic diseases; that is, people whose diets are high in fruits and vegetables have a lower risk of developing various types of cancer, including breast and colon cancers. More in-depth studies have focused on vitamin C as one of the key nutrients in fruits and vegetables that provides protective activities.
A higher body level of vitamin C is associated with a lower risk of strokes, atherosclerosis, and of dying from cardiovascular disease (CVD). Vitamin C may offer protection from CVD by its effect on cholesterol: higher vitamin C levels in the body have been correlated with lower total cholesterol and LDL (harmful) cholesterol levels. Vitamin C also works together with vitamin E by restoring vitamin E to its functional, active form after it has been dismantled by free radicals, which is another way vitamin C may offer protection from CVD.
Clinical studies with vitamin C have suggested its use in counteracting or as a protective agent against many other conditions, such as colds and some infection diseases. Vitamin C is found at lower levels in people with Helicobacter pylori, a very common bacterial infection of the stomach that is related to ulcers and other upper gastrointestinal complaints. In addition to its protective effects against disease, Vitamin C is necessary to support many normal processes in your body. Although many animals can make their own Vitamin C, for humans, it is an essential vitamin, meaning that we cannot make it but must obtain it from the food we eat.
Vitamin C can easily be destroyed by prolonged storage and/or excess light. This is one of the reasons whole, fresh fruits and vegetables are a better source for this important nutrient than processed foods. Another reason whole foods are a better way of getting vitamin C is that it functions as part of a nutrient team that includes such nutrients as vitamin E (mentioned above) and the carotenoids, which are also in whole foods but are often either not present or present in greatly reduced amounts in a processed food. Excellent sources of vitamin C include raw vegetables such as papaya, bell peppers, broccoli, Brussels sprouts, strawberries, pineapple, oranges, kiwifruit, cantaloupe, cauliflower, kale, cabbage, bok choy, and grapefruit.
Carotenoids are a group of phytonutrients that lend the red, orange and yellow hues to fruits and vegetables. Carotenoids are present in all living organisms, but humans are not able to make them and must get them from food. Some carotenoids can be converted in your body to vitamin A; however, the reason carotenoids have received so much recent attention has more to do with their significant antioxidant effects, and the many studies that have shown an association between consumption of foods high in carotenoids and lower risk of degenerative diseases such as macular degeneration, and cancers such as prostate cancer.
The carotenoids found in foods are varied, and over 60 different carotenoids have been identified. In humans, at least eight of these have been shown to be absorbed and to have beneficial activities. Of these carotenoids, beta-carotene is the most recognized and talked about since the earliest studies on carotenoids found an association between high levels of beta-carotene consumption and a decrease in strokes and CVD. Recent studies, however, suggest that the full spectrum of carotenoids, which are found naturally together in the World's Healthiest Foods, are needed for the most benefit.
Of the varied carotenoids found in humans, lycopene is present in the blood in the highest concentration. Lycopene is found in tomatoes and pink grapefruit, and is the carotenoid associated with protection from prostate cancer. Lutein, another carotenoid in vegetables, accumulates in the eye and is associated with protection against the development of macular degeneration associated with aging. Given this range of activities from different carotenoids, it is important that you receive all of these important phytonutrients, not just beta-carotene.
Generally, supplements of carotenoids contain mainly one or two types of these important molecules, not the full spectrum. The best way to receive the full spectrum of beneficial carotenoids is to eat a varied diet of the World's Healthiest Foods, especially those fruits and vegetables providing a range of colors. Concentrated sources of carotenoids include carrots, sweet potatoes, tomatoes, chard, and asparagus.
Vitamin E is another essential vitamin found in whole foods that has significant health promotion activities. An excellent antioxidant, vitamin E is important for the integrity of all of your cells' membranes—the protective gateways that allow nutrients in and wastes out, while keeping potentially destructive molecules from entering your cells. Vitamin E has been shown to protect from arterial damage, which it does by directly inhibiting the production of the damaging molecule, oxidized LDL cholesterol. The importance of vitamin E can be seen from a recent survey by the Council for Responsible Nutrition, in which it was found that cardiologists are more than two times as likely as other Americans to take vitamin E, and 75 percent of cardiologists surveyed promote vitamin E to their patients on a regular basis. In addition, a deficiency of vitamin E has been linked to neurological conditions and a higher risk of many types of cancers.
Although vitamin E supplements are popular, the problem with these supplements is that vitamin E is really a family of eight different nutrients, called the tocopherols and the tocotrienols. Many supplements only contain one member of this vitamin E family, whereas a natural source, such as wheat germ, contains naturally balanced amounts of the entire vitamin E family. In addition, the bioavailability of natural vitamin E is higher than that of synthetic vitamin E (dl-alpha tocopherol), which means that more vitamin E from a natural source actually gets into your body and is active than is synthetic vitamin E. Excellent sources of vitamin E include sunflower seeds, spinach, Swiss chard, turnip greens, asparagus, beet greens, and mustard greens. Very good sources include almonds, broccoli, bell peppers, kale, and tomatoes.
Whole grains are a rich source of the minerals your body needs to support many day-to-day functions (such as the production of ATP, the body's fuel) that keep you full of energy and able to fight disease. Selenium is an example of a mineral you get from whole grains that is integral to your health and well-being. Like many minerals, selenium is used by a variety of different proteins in your body, like the enzymes that protect you from toxins and infectious bacteria. One especially important example is glutathione peroxidase, an enzyme that is present in most of your cells and is important in maintaining the level of glutahione, an anti-oxidant your body creates that protects your cells against damaging toxins and oxidants.
Because selenium is used by a variety of protective proteins, dietary consumption of adequate amounts of selenium has been associated with a reduced risk of many chronic and degenerative diseases. The most exciting recent studies are those that link selenium to protection from developing cancers of the respiratory and gastrointestinal tracts. This relationship between selenium intake and cancer prevention is so apparent that the National Cancer Institute, a governmental agency that focuses on diet and health, has established a study to investigate the role of selenium in cancer prevention.
Along with its association with a reduced risk of cancer, a relationship between higher intakes of selenium and a lower risk of CVD has also been suggested. Selenium may support an increase in HDL (the beneficial type of cholesterol) as well as being able to reduce platelet aggregation.
The amount of selenium in a food is directly related to the amount present in the soil in which the food was grown; therefore, organically grown foods—those that have been rotated and grown in a more natural environment—are more likely to have higher selenium content. Excellent sources of selenium include tuna, shrimp, sardines, salmon, cod, crimini mushrooms, shiitake mushrooms, asparagus, and mustard seeds. Very good sources of selenium include turkey, chicken, lamb, scallops, beef, barley, tofu, and eggs.
Fish and the Important Omega-3 Fatty Acids
Fish are an excellent source of selenium. They also provide another extremely important nutrient: the omega-3 fatty acids. Omega-3 fatty acids are polyunsaturated fats that are critical components of the membranes in every one of your cell, so they are absolutely vital to your body's ability to function properly. The parent omega-3 fatty acid, the one from which all others are made, is alpha-linolenic acid, and it is essential because your body can't make it, therefore, it must be obtained from your diet.
Medical scientists first became interested in the health benefits of omega-3 fatty acids when it was observed that people with higher levels of omega-3 fatty acids in their red blood cells show a 70 percent reduced risk of experiencing a heart attack compared to those with lower levels. Many studies have been performed on these intersting fats, and the most beneficial fats of them all appear to be the longest chain omega-3 fatty acids, docosahexaenoic acid (DHA) and ecosiapentaenoic acid (EPA), which are found in fish and algae. EPA and DHA can also be made in your body from the parent omega-3 fatty acid, alpha-linolenic acid.
Most recent interest in the omega-3 fatty acids has centered around the function of DHA and EPA as precursors to the anti-inflammatory molecules in your body. As a result of their ability to lessen inflammation, EPA and DHA have been shown to decrease symptoms associated with rheumatoid arthritis and may alleviate progression of this disease. These omega-3 fatty acids have also been used to decrease symptoms in people with many other types of inflammatory conditions, such as asthma and inflammatory bowel disease. Since these fatty acids are important for the manufacture of anti-inflammatory chemicals, they also help to promote optimal skin health by reducing the redness, dryness and itching that are symptomatic of inflammation.
Studies have also shown that DHA appears to be lower in red blood cell membranes from boys with attention deficit disorder (ADD) as compared to those who don't experience ADD. In addition, people who frequently consume fish appear to have a lower likelihood of experiencing depression than those who rarely consume these EPA/DHA-rich foods, and those with major depression have also been found to have lower concentrations of these omega-3 fatty acids in their bloodstream.
EPA and DHA are found in high levels in wild-caught tuna and salmon. EPA and DHA can be made in your body from the essential omega-3 fatty acid, alpha-linolenic acid, and excellent sources of this fatty acid include flax seed and walnut. Sardines and salmon are very good sources of omega-3 fatty acids because of their concentration of EPA and DHA. Other seafood such as shrimp and cod are good sources of omega-3 fatty acids.
The Healthy Monounsaturated Fats
Another type of 'good fats' found in whole foods are the monounsaturated fats. Olive oil is the best-known source of these monounsaturated fats, which have names such as oleic acid, myristoleic acid and palmitoleic acid.
Monounsaturated fats gained most of their good reputation for health promotion after researchers found that people who eat diets high in monounsaturated fats have a lower incidence of heart disease. Greeks, in particular, have a four-fold lower incidence of heart disease despite the fact that their diet is high in fat. The fat in the Greek diet is mainly olive oil, an excellent source of monounsaturated fats.
Olive oil has benefits other than just its monounsaturated fat; it also contains many phytonutrients that show good antioxidant activity. This may be why consumption of olive oil is associated with lower risks of developing cardiovascular disease, rheumatoid arthritis and certain types of cancer. Virgin olive oil contains the highest amounts of these antioxidant phytonutrients. As the olive oil is more and more processed, these antioxidants are removed. Other rich sources of monounsaturated fats include avocado; nuts such as almonds, cashews, and peanuts; and seeds such as mustard and pumpkin seeds.
The World's Healthiest Foods and the Beneficial Fibers
Dietary fiber is now well accepted as a nutrient necessary for health. Fiber helps speed the movement of food through the intestines during digestion, so the body can rid itself of potentially toxic wastes more quickly. Dietary fiber has been associated with protection from heart disease, lower total cholesterol levels, and a decrease in the risk of cancers such as colon cancer and breast cancer. People with diabetes may also benefit from eating foods high in dietary fiber since these foods have been shown to reduce blood sugar levels.
Fibers are classified as soluble and insoluble. The insoluble fibers generally promote excretion, whereas the soluble fibers support the function of the intestinal tract and help decrease blood glucose levels. It's important for you to obtain a good balance of both soluble and insoluble fibers. Whole grains are concentrated source of insoluble fibers, and fruit skins provide high amounts of soluble fiber. Excellent sources of fiber include navy beans, raspberries, collard greens, turnip green, beet greens, and cinnamon. Very good sources of fiber include beans and legumes, barley, wheat, winter squash, pears, broccoli, and spinach.
Chemicals in Processed Foods
Not only do the beneficial components contained in the World's Healthiest Foods favorably impact their health-promoting potential, but what they do not contain is just as important. The World's Healthiest Foods, when organically grown and minimally processed, do not feature the array of chemical pesticides and additives found in conventionally grown and refined foods. The scientific evidence strongly suggests that many of these chemicals are harmful to human health.
For more discussion, see Q&A "What Are the Problems with Conventional Foods?".
Medical researchers are in agreement that diets high in fruits, vegetables and whole grains promote health and prevent disease. Furthermore, pesticides and many food additive are known to pose a threat for promoting cancers in humans. The food that you choose does make a difference. When you eat the World's Healthiest Foods, you'll eat a variety of fruits, vegetables and whole grains. A key word here is 'variety.' It may be mathematically impossible for you to meet your nutrient goals from a limited spectrum of foods! (That sobering conclusion applied to 3 out of every 4 adults in France when the limited variety of their diets was analyzed by nutrition researchers.) Choose a colorful palette of foods. Eat raw or lightly cooked vegetables and fruits whenever you can, and choose organic foods if possible. These steps will provide you with the full spectrum of nutrients and phytonutrients that will translate to a long life of abundant energy and optimal wellness.