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Nutrition for the 21st Century: Issues and Opinions
There may have been many different environments in which ancient man found it possible to survive, but it was the rich diversity of the plant world that provided the background for the evolution of man. Homo Sapiens (the species of all humans today) evolved over 50,000 years ago in response to a nutritional environment that was largely plant-based and had been in existence for over 2 billion years evolving in response to predators and climate. The plant foods available were most typically low in fat, high in fiber, and rich in the special preventive substances found only in plants (phytonutrients). This diverse diet provided all the elements needed for a long life, and we have evidence that ancient man knew the medicinal properties of the plant world as well. The discovery of agriculture 10,000 years ago meant that the biodiversity of the diet was narrowed by an emphasis on those plants that could be easily cultivated. The Industrial Revolution 200 years ago meant that many foods would be processed for economic gain, resulting in a further separation of man from his plant-based environment and further imbalances due to the refining away of the husks of grains such as rice or the refining of oils resulting in the loss of vitamins.
Today we find ourselves with an epidemic of overnutrition and obesity in the industrialized world with some foods that may promote heart disease and cancer. While we derive more than enough calories from our foods, we have lost many of the natural preventive substances that provided the checks and balances in our bodies. Can we go back in the future and return to a diet and lifestyle where everything we need for our sustenance will be in perfect balance with our bodies in the next century? Can we use genetic engineering, a knowledge of our own genes and those of the plants and other foods we eat to fine tune our human bodies to prevent heart disease and cancer and prolong life far beyond what we ever thought possible? I believe that the answer is a resounding YES.
Achieving the necessary breakthroughs in nutrition, physiology, and genetics will require an interdisciplinary team approaching the solutions to heart disease, cancer and aging from a new perspective - human nutrition. The UCLA Center for Human Nutrition which I direct is dedicated to achieving this vision. Our Center is approaching this challenge with a team of over 100 scientists drawn from many different fields of medicine and science.
The killer diseases, heart disease and cancer, and aging each result from an interaction of genes and environment leading to changes in the functioning of the cells. Once we know the entire human genome, we will only be at the beginning of our journey to end these diseases and extend lifespan. In the UCLA Center for Human Nutrition, researchers recently found that a gene coding for an enzyme implicated in activating colon cancer-causing chemicals from smoked meat could be found in about 20 different versions in different individuals. While the gene in each individual made the same enzyme (N-acetyl transferase), there were differences in the structure of the gene that defined different individuals in the same way as a fingerprint would. It was found that individuals with a certain fingerprint (called a polymorphism) for this particular gene would be protected from developing colon cancer, but only if they ate broccoli and other cruciferous vegetables. If there was no evidence of eating these vegetables, there was no protection regardless of the genes that each individual had in place. This discovery showed that for this gene and possibly others the information on how to react to the nutritional environment is encoded in our genes.
When cancers and pre-cancer cells are examined they are full of damaged genes. The process of cancer itself progresses through a series of mutations in the DNA of the cancer cell over a ten to fifteen year period. In both Israel and Japan, heavy smokers have less than half the incidence of lung cancer we have in this country. Those who eat more fruits and vegetables appear to be those who are protected. The American people do not eat enough fruits and vegetables, cereals and grains, dietary fiber, or in many cases enough high quality protein. One of three women and one of two men will be diagnosed with some form of cancer during their lifetime. It is entirely possible that the high incidence of cancer in this country is due to the diet we eat, or rather the one we don’t eat.
High calories, high fat, lots of polyunsaturated fats, an epidemic of obesity, and smoking all put a stress on our cellular repair systems. As we age our ability to rid our bodies of the abnormal cells that result from this damage wanes and cancer can get a foothold. Food security is no longer a technical problem. We can grow enough to feed the whole world. Food security is a political and social problem. The impact on the environment of growing populations, and the distribution of food have much more to do with wiping out malnutrition than science does. As the world’s population continues to grow, the need for food is expected to double in the next 30 years. Through agricultural biotechnology, there are already prospects for producing food for people on existing farmland well into the future. Preserving the earth’s environment and our internal environments will be the scientific challenge. This challenge will require an increased knowledge of how our genes interact with our diet. We already know something about these issues, and there is much you could already be doing that will improve your quality of life and hopefully extend your lifespan.
Our diets must be changed now. Recommendations made in the late 1980’s by the Surgeon General, the American Cancer Society, the American Heart Association and every government agency concerned with nutrition have still not been put into action. The UCLA Center for Human Nutrition has developed a pyramid called the California Cuisine Pyramid. This pyramid was designed by me and my colleagues to meet understandable goals for eating fruits and vegetables to get special preventive nutrients (phytonutrients), eating whole grain cereals and breads to reach a fiber goal, eating plant-derived protein and some animal protein to meet specific protein goals, and adding taste enhancers including natural oils from avocado, nuts, seeds, tasty spices, and sweeteners to make the foods we eat for health enjoyable. This pyramid and the diets specific to it are designed for preventing cancer and heart disease and go well beyond the U.S. Department of Agriculture Food Guide Pyramid.
The so-called basic four food groups and other medical and dietetic diets popularized after World War II evolved since the discovery of agriculture some 10,000 years ago and have succeeded in wiping out famine and hunger in wealthy societies. We have accomplished this important task and it has had more of an impact in reducing deaths from tuberculosis, pneumonia, and other infectious diseases than all the antibiotics and other medicines combined. Nutrition and sanitation are public health strategies that are far more powerful than drugs and surgery. We have overdone it by creating an epidemic of obesity in the United States and throughout the world. Obesity is the result of an interaction of genes and environment and is a risk factor for heart disease and cancer.
Malnutrition is bad for the immune system. Malnourished children get infected and die. When they are fed, their immune systems are revived and they can respond to penicillin and other antibiotics. However, there is a long-term price to be paid for modern convenient cost-effective overnutrition. Overnutrition sends growth signals to every cell in the body and this overgrowth leads to mutations in genes. Some of these lead to heart disease, cancer or premature aging.
These ideas are part science fiction as we move into the imagined progress of the next century, but it also will help the American people at the end of this century. Finally, if you have ever thought about becoming politically active about your health now is the time. Nutrition represents a public health approach to medicine that was first articulated by Hippocrates in the year 500 B.C. " Food is medicine, and medicine is food".
Summary of the USDA Food Pyramid Dietary Recommendations
California Cuisine Pyramid
2. It is important to eat fruits and vegetables to get phytochemicals and many micronutrients unique to these plant-derived products. 5 to 11 servings of fruits and vegetables per day.
3. There 50,000 edible plant species of which we eat only about 150 to 200. Increased biodiversity is desirable.
4. The produce section has economic and practical disadvantages in the grocery store compared to other categories, and needs special encouragement for increased consumption.
5. Cereals and grains have not been differentiated by fiber content. A unique function of this group is to provide soluble and insoluble fiber which affects hormones and gastrointestinal function. Americans eat 10 to 15 gm/day, but should eat 25 to 35 g/day which can only be achieved by emphasizing high fiber cereals and grains. 6 to 9 servings should be able to achieve this.
6. Protein chosen from either the plant-derived or animal-derived sources can be used. It is recognized that it is not the source of the protein, but the choices and quantities to meet protein adequacy throughout the lifecycle that is important. 4 to 6 servings should be chosen to achieve the appropriate protein goal.
7. Taste is at the top of the pyramid, because it is the most important element in encouraging food intake. Instead of the dots symbolizing hidden fats and oils (in the traditional USDA pyramid), use natural flavor enhancers including the avocado, herbs, nuts, olives, seeds, spices (including garlic, chilis, onions, cumin, curry, mustard, peppers), oils rich in monounsaturates and omega-3 fatty acids, and sweeteners (honey, molasses, sugars, artificial sweeteners).
Best Food Sources of Antioxidants
Lecture 1:Introduction to Nutrition in Western Civilization
Lecture 2: Dietary Macronutrients, Body Fat, and Blood Lipids
Lecture 3:Digestion and Absorption of Macronutrients
Lecture 4:Basic Principles of Nutrient Metabolism
Lecture 6:Fuel Utilization During Exercise
Lecture 7:Biochemistry of Oxidant Stress in Health and Disease Antioxidants
Lecture 8:Nutrition for the 21st Century