Perhaps you Gaylords will learn something:
Food For Thought: An Interview with Nutrition Scientist Dr. Paul Saltman
Department of Biology, University of California, San Diego, CA, USA
by Sean Henahan, Access Excellence
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We are barraged by the media with endless claims and promises about the value or risks of what we eat and drink and what we take in the way of dietary supplements. Where is the science? I spoke with nutrition science authority Dr. Paul Saltman, professor of biology at UCSD, and author of various texts and popular books about the science of nutrition, in an effort to separate some nutrition facts from food fiction.
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Q: We hear so many claims and promises about what's good for us and so many pronouncements about what's bad for us to eat. How can a person bring a scientific approach to the task of sorting through all this information?
A: I have a basic premise when I teach about food and nutrition. Food is metaphysics. What we eat, when and how much, has much to do with our culture and religions, our economic and social environment, with our age and lifestyle. Although it provides the nutrients by which we live, food is not in itself a science, it is a sensual experience required for survival.
Nutrition, in contrast, is an exact science. It is experimentally verifiable through the strategies of what is known as total parenteral nutrition (TPN), i.e. intravenous feeding. With TPN feeding all of the nutrients that a human being needs from the time of infancy to the latter years one can be maintained alive and well and growing without ever eating a morsel of food or drinking a drop of liquid.
This is the science. We know there are 44 chemical nutrients required for TPN. We understand what their chemistry is and what their structures are. There is nothing esoteric or magic about it. These nutrients are not kosher, not Szechuan or Cantonese, not chocolate or vanilla, they are chemicals. These 44 chemicals really constitute the true staff of life.
Q: Humans have evolved relatively rapidly from a caveman existence to the world of today. Can we learn anything about human nutrition by looking at what our prehistoric ancestors ate? For example, some people like to claim that we evolved while eating a diet primarily composed of forage.
A: There is good news and bad news. Those of us that have the luxury of adequate nutrition and supplies of clean water and the ability to get rid of our wastes have a longer lifespan and better health than do those who are less fortunate. We've learned about agriculture, public health, even about medicine. The bad news is that, in the developed nations at least, when you have ample supplies of inexpensive foods that taste good, we get obesity and the consequences of obesity, which are enormous.
We have evolved. The Pima Indians evolved to meet the needs of living in the desert. In their case genetic selection was for those with the most effective metabolism and ability to conserve scarce resources. Make available a 7-11 and a six pack of beer to people with this genetic background and you've got people who are very obese and very sick from heart disease and diabetes.
We are living longer and reproducing more. We have challenged the planet because of the growing population, using energy and resources in a way which frequently becomes deleterious, but need not be. The issue is how do we balance this well being from man commandeering the world versus the needs of the roughly two-thirds of the population that do not get enough to eat.
The cave-man model of the primal vegetarian diet makes no sense. It is Rousseau's notion of the noble savage. It is nonsense. We should go back even before man, to chimpanzees. It is often said that these beautiful primates, precursors of humankind, are vegetarians. They are not. They love meat. Indeed, recent research shows they will really hunt to get meat, and using a human analogy, will use meat to beg for sex. We did not evolve from a vegetarian culture. We became less vegetarian and more dependent on meat in our diet as a consequence of being able to raise via animal husbandry, animal sources of protein.
I believe obesity is the root cause of many forms of cancer, heart disease and stroke and many other aspects of human disease. But we are living longer now with our current diet than Cro-Magnon ever did. The reason Cro-Magnon's didn't have a lot of cancer is that they didn't live long enough to get cancer.
Q: Some of the first scientific understanding of essential nutrients came with the observation that a lack of certain nutrients was associated with some disease states, for example, scurvy. How has the study of nutritional deficiency contributed to the science of nutrition?
A:One of the first cases studied carefully was the case of polished rice and beri-beri in the Dutch East Indies. Dr. Eichman found that polished rice caused this terrible disease and that eating the rice polishings that had been removed would relieve the symptoms of the disease. That was a beautiful demonstration of a thiamine deficiency disease.
The subsequent isolation of the different vitamins led us to understand through the vitamins (one of only six of essential nutrients groups) some mechanisms of action of specific nutrients. This led to a way of looking at nutrition considering the mechanisms of water, calories, carbohydrates, fats, proteins, amino acids, minerals. This is a whole different way of knowing why and how these 44 nutrients are essential for the human organism to thrive grow and reproduce.
Vitamins are only part of the story. For example it is equally important that we understand the mechanisms of how calcium is used, how potassium and sodium are in balance in terms of electrolyte balance inside and outside a cell, and why magnesium is required, and how phosphate serves the body. These are every bit as important as knowing about vitamin C and its role as a co-factor in the hydroxylation reactions of proteins.
Q: Antioxidant vitamins get a lot of attention these days. Go into a vitamin store and you will see promises of eternal youth. But these promises are made on supposedly scientific grounds. What's going on here?
A: Let me say unequivocally. There is no unambiguous double-blind, prospective controlled experiment that show that doses of antioxidants greater than those required by the USDA allowances have any value as a protectors against disease, or as curative agents once a disease occurs, other than in the case of deficiency disease. The notion of mega-dosing popularized by Linus Pauling with vitamin C, has yet to be proven in an unambiguous fashion. That bothers me. If I believed that there was data supporting the use of mega-doses of antioxidants, I would be swilling E, and taking mega-doses of C faster than anyone. However, I don't see that data.
We know oxidative damage occurs in tissues. I've studied the role of iron and copper in nutrition. These elements are required for life. but in excess or bound in wrong fashion they can cause free radical damage. I believe vitamin C is an antioxidant but I also know it can be a pro-oxidant under proper circumstances and can cause extensive damage to cells and tissues.
Because I know that oxidative damage is bad doesn't mean that anti-oxidants are good over and above what has been found to be required in experimental studies.
Q: Will it ever be possible to answer these claims one way or another with scientific studies?
A: Yes, I believe so. Prospective studies with antioxidants are underway. Science requires repeatable experiments. If a nutrient is useful you will see an effect. We went down into Durango, Mexico with Mexican physicians and fortified the milk with iron and copper. We were able to demonstrate in controlled double blind studies that in children who didn't look anemic we could move hemoglobin concentrations 20% above where they started. This is a marked increase. We know the better your hemoglobin levels, the more oxygen you deliver, the better your myoglobins and cytochromes. This in turn produces better vitality, health and growth.
Q: The WHO has numerous programs to provide fortification and supplements of essential nutrients.
A: These programs have emphasized the importance of both micronutrients and macronutrients. There are good examples where adding nutrients such as amino acids and calcium have made a difference in public health.
Q: Calcium is a good example of complementary nutrients. It's not just a matter of taking calcium is it?
A: Prospective studies with calcium show that if women take RDA amounts of calcium it will increase bone density. Adding trace elements can add bone density for post-menopausal women. These are facts demonstrated by prospective studies. On the one hand, if women took 1000 mg of calcium per day with or without vitamin D they will increase bone density. But, women should also take vitamin D, fluoride, trace elements and get exercise. And if post-menopausal, women should consult a physician regarding hormone replacement therapy. All of these factors play a fundamental role in health and maintenance of skeletal tissue.
Similarly, iron is much more effectively used when taken with copper. If you add one copper for every ten irons, you can get by with a lot less iron. We also know that sugar, organic acids and other molecules in the diet enhance the uptake of the various metal elements.
Q: At the moment there is a new push at WHO to include long chain polyunsaturated fatty acids (PUFAs) in formula Q: fatty acids. LC-PUFAs and formula.
A: That is a small part of the fat problem. Infants need PUFAs. We all do. The issue with formula is that you want to mimic as much as possible what's in human mothers milk. Everyone in the pediatric community agrees mothers milk is the best way to sustain growth and development in the child. So with formula the issue is, if the mothers' milk has PUFAs, so should the formula.
Q: Fat is often portrayed as the enemy for adults trying to eat a healthy diet. Is fat all bad?
A: We live in world filled with fear of fats and cholesterol. People and organizations proclaim that 30% fat in the diet will make us healthy. Yet, when we go back to TPN, the IV bag can contain as much as 55% calories in fat. People receiving TPN do not get fat on this diet. They are not obese and don't have heart disease. The French diet is about 45% calories from fat, yet they have half the level of obesity, and half the level of heart disease of this country.
The physics of calories states that all calories are equal. That is a thermodynamic truth. A calorie from fat equals a calorie from carbohydrate.
So what's wrong with fat? Fat makes food taste good. When food tastes good, you eat more. Eat more calories you get fat. Obesity is the number one nutritional disease in USA. It is a disease of self-abuse, with more calories in the than out. If we eat more than we exercise, more than our basal metabolic rate can sustain. we suffer the physiological detriments from that obesity. If we could control obesity we would have major handle on one of the biggest panoramas of health problems in America today.
There is some confusion about PUFAs. We know that these essential fatty acids are required as precursors to make prostaglandins and related compounds necessary for cell membrane structure. In general PUFAs are said to make good fat, i.e. high-density lipoprotein, where saturated fats make the low density lipoprotein. Good guys, bad guys, we're back into metaphysics. The point is that some fatty acids relate to the balance between high density and low density lipoproteins. However, the most important issue is your total glyceride concentration in your blood stream. That is what correlates best with obesity.
Q: There are guidelines handed down from above on what constitutes a healthy diet. What is a rational person to make of these generalized guidelines?
A: This is a very complicated question. Part of me says bless the FDA and USDA for all of the research that has taken place in the 20th century. This research has brought nutrition to be an exact science and has given the term 'nutrition' meaning in this country in terms of developing the well being of the people. Whether you are talking about six basic food groups or four basic food groups, circles that look like peace signs or triangles and pyramids, the notion that people are concerned about the health of the nation is good.
But these guidelines have not been without problems. For example, George McGovern's committee formulating the 'Diet for a Healthy America' made terrible mistakes, scientifically as well as intellectually in terms of the belief that you can tell people what to eat and what to do and that's going to make them better, healthier people. It's important to remember that nutrition guidelines are made by committee.
