Health

Discussion About Dietary Supplements and Needs

Thomas G. Sherman, Ph.D., was online Tuesday, June 20, at 2 p.m. ET to field questions and comments about dietary supplements and dietary needs. Sherman is an associate professor in the Department of Physiology and Biophysics at Georgetown University Medical Center.

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The transcript follows.

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Thomas G. Sherman, Ph.D.: Welcome everyone to this afternoon's discussion on nutrition and dietary supplements. Although I have a broad range of interests, both professional and personal, nutrition is one of my favorites because it generates so much passion, and so many questions, with nearly everyone. Because we all recognize how important our eating habits are to our health, and because many people fail to eat as well as they should, it is common to seek that magic dietary supplement, vitamin or fad diet to make up for or correct our dietary transgressions. Although such a magic supplement has yet to be identified, there are some strategies for attaining and maintaining a healthy diet that, hopefully, we can talk about today, so I welcome your questions.

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El Dorado, Ariz.: Fish oil - I know it is important. I cannot seem to tolerate it in any form - liquid, pills, etc. I know I need Omega-3's, and although I try, my diet doesn't provide enough. Is there another way to get them?

Thomas G. Sherman, Ph.D.: Vegans and some vegetarians run into the same difficulty, although for different reasons. The problem, of course, is that adequate omega-3 fatty acid intake is one of the most important aspects of a healthy diet. For non-vegans and meat eaters, fish is the standard recommendation for getting such nutrients, but for everyone, nuts provide the best solution. Nuts, such as walnuts and pecans, are frequently avoided because they are "high in fat," but it would be more accurate to describe them as high in mono- and poly-unsaturated fat, which includes the omega-3 fatty acids. My favorite combination is walnuts and pecans, either as a topping on my granola or in my amazing banana nut buckwheat pancakes, because walnuts are very rich in polyunsaturated fats and pecans are very rich in monounsaturated fats. Flax seed, soybeans, and winter squash are also foods rich in omega-3 fatty acids. Try them.

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New York, New York: I do aerobic exercise about 45 minutes 5-7 times per week and strength train 2x per week. I follow a strict diet that emphasizes whole grains, fruit, vegetables, beans with small amounts of fish, all to keep cholesterol low. I am wondering if protein drinks such as whey and whey/casein, or soy isolate would make sense for supplementing this diet. I take a multiple vitamin.

Thomas G. Sherman, Ph.D.: Keep up the good work. Getting enough protein in our diets is easy, and the protein requirements for even very physically active individuals are not that different. The only reason to add protein drinks to your diet would be if you want to add muscle mass, and even then, it works best if you do so within the first 30 minutes after a workout. As a runner, I avoid doing this because I prefer lean muscle without the bulk. Other than the financial costs, there are no significant safety or health concerns associated with protein supplementation.

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Anonymous: What is the harmful effect to your body by taking weight gaining products such as whey protein sold by GNC and and other companies.

My husband is very healthy but he is weights only 110 pounds (5'4").

Thomas G. Sherman, Ph.D.: As I just mentioned, one can add muscle mass by taking protein rich foods or protein drinks after a workout. Although there is some evidence that calcium excretion increases with increasing protein intake, this is more of a concern in the elderly not taking enough vitamin D and who are already at risk for weak bones. Also, increased protein intake is harder on the kidneys, but again, for most healthy people, this is not a concern. To diminish the financial impact, try concocting your own protein rich shakes and eat nuts. Good luck.

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Woodland Hills, Calif.: What do you think about all the studies and experts that are calling for the DRI of vitamin D to be raised to 1,000 IU? Do you support this? Do you think it's important to get that much of vitamin D?

Thomas G. Sherman, Ph.D.: The evidence is very compelling that up to 95% of people have insufficient levels of vitamin D, and I agree that it is likely that 1,000 IU of vitamin D should be the new DRI, especially for the elderly who largely stay out of the sun. Even though we enjoy one of the highest rates of daily calcium consumption in this country, our rates of bone fractures is also among the highest, and the evidence suggests this is due to deficits in vitamin D.

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Washington, D.C.: What is the best substitute for butter in recipes that call for it?

Thomas G. Sherman, Ph.D.: I use canola oil frequently, or replace half of the butter, if necessary, with canola oil. I have a ginger cookie recipe, for example, that I frequently fantasize about that has no butter. I also sometimes substitute apple sauce for butter, and this works well in some cakes. There are olive oil and other, non-trans fats containing margarines now available, but I have yet to try them in baking.

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Washington, D.C.: Last night while watching the show on food in Thailand they spoke about Spirulina. Is it safe or healthy...is it worth while for a someone who does not eat enough greens? Thanks

Thomas G. Sherman, Ph.D.: Spirulina is a harmless alga, and it contains nutrients with some value, such as vitamin A and mixed carotenoids. Although it has been touted as such, there is no good evidence that it lowers cholesterol or decreases appetite. Similarly, spirulina is not a good vegetarian source of vegetarian vitamin B12. (Shameless plug alert!!!) A good source of information on questions like this is the book "The 5-Minute Herb & Dietary Supplement Consult" by Dr. Adriane Fugh-Berman, an Associate Professor in my department here at Georgetown.

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Anonymous: How important is cholesterol to the human body? Do you feel it is being incorrectly blamed for heart disease?

Thomas G. Sherman, Ph.D.: Cholesterol is a fundamental part of all membranes, and helps maintain the structural integrity and fluidity of the membrane. Except for those people with familial (genetic) forms of hypercholesterolemia, dietary cholesterol has almost no impact on plasma levels of cholesterol. The oxidative LDL model of atherosclerosis, which implicates LDL cholesterol with arterial plaque formation, is a sound hypothesis, but remains controversial. I think dietary cholesterol is unfairly blamed, perhaps, but circulating cholesterol levels are definitely associated with heart disease.

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Anonymous: I recently had a debate with a family member and thought you could help. Which do you feel is more important to health? Exercise or Nutrition?

Thomas G. Sherman, Ph.D.: Exercise and nutrition of completely linked, so it is difficult to answer. For example, whereas calcium and vitamin D will help build bone, that bone can be brittle unless sufficiently stressed during the course of even moderate, low-impact exercise. Similarly, as one decreased fat mass and builds muscle mass, your resting rates of metabolism will be higher, and it will be easier to regulate blood glucose levels and insulin sensitivity.

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Los Angeles, Calif.: Would you recommend that we take a multivitamin suited for our specific gender and age?

Thomas G. Sherman, Ph.D.: I like the descriptions of taking a multivitamin as a sort of insurance policy; they don't take the place of a good diet, but they help round out the rough edges. The two vitamins I recommend most are Folate and Vitamin D. Vitamin D I have already discussed, and the need for folate, or folic acid, is easy to understand, especially for women, and even more especially for women who drink alcohol. Folate supplementation has largely eliminated neural tube birth defects, which is a major success story in public health policy, but also important is the role that folate plays in breast cancer. We have known for some time that alcohol consumption increases the risk of breast cancer in women, but this risk goes away in women who take more than 400 microgram/day of folate, and significant benefits are observed in women who take more than 600 microgram/day.

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Birmingham, Ala.: I have a question about the efficacy of cranberry or mannose supplements to decrease or fend off kidney infections?

Thomas G. Sherman, Ph.D.: Cranberry juice has antibacterial qualities that may have some useful abilities to lower bacteria concentrations in the urine (bacteriuria) and decreasing the risk of urinary tract infections (UTI). Drinking 300 ml of cranberry juice per day makes the urine more acidic, which decreases the ability of bacteria to adhere to the bladder and urinary tract tissues, thus decreasing the incidence of bacteriuria. Unfortunately, this decreased bacteriuria is not necessarily associated with a decreased incidence of UTI or decreased symptomatic infections. On the other hand, cranberry juice is delicious and contains lots of vitamin C, so drinking it has some definite beneficial side-effects.

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Thomas G. Sherman, Ph.D.: It would appear that question marks appear where I type the symbol for micro; thus ?g is a microgram. My apologies.

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New York, N.Y.: I've just learned that I'm vitamin B12 deficient. How concerned should I be?

Thomas G. Sherman, Ph.D.: Vitamin B12 deficiency is common, and not only among vegetarians. although there are vegetarian sources of vitamin B12, such as some algae and sea vegetables, vitamin B12 is almost exclusively limited to animal sources. Vitamin B12 deficiency is associated with macrocytic anemia and pernicious anemia because this vitamin is an important element in the blood cell formation. Furthermore, such deficiency might a sign of some other problem, like an absorption problem, infection, or dietary problem. On the other hand, measuring vitamin B12 levels is problematic, and I would not automatically assume that you are deficient if you feel your diet is otherwise good. Look into it.

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Thomas G. Sherman, Ph.D.: Clearly one of the main frustrations felt by the public over research in nutrition is the publication and reporting of seemingly contradictory findings; on one day, fiber is recommended, and on the next day, fiber intake offers no protection for colon cancer. Unfortunately, and understandably, this as contributed to a cloud of skepticism over science in general. In part, this reflects the incredible difficulty in doing human research - there are too many variables, too many unknowns, and a huge genetic variability between people. It is so much easier doing research on an inbred strain of mice. But nutrition, in general, also makes it more difficult. People eat a tremendous variety of foods, and trying to determine what exactly they eat and in what amounts is almost impossible. We try to make up for these errors by creating huge study populations, like the Women's Health Initiative or the Nurses Health Study. As scientists, we are optimistically waiting for the preponderance of the data to point in a certain direction, and for the errors to cancel each other out. What we see reflecting the normal scientific method is published as, and perceived as, flip-flops or random. We need to do a better job getting the public to understand this.

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Providence, R.I.: Do you see any benefit in taking glucosamine and amino acid supplements?

Thomas G. Sherman, Ph.D.: No, unfortunately. Although there is an attempt to do some sub-group analysis on the recent, largely negative, NIH glucosamine/chondroitin sulfate trial, there appears no significant reason to take this supplement. As a runner, I used to take them and was convinced they were helping me, but I stopped several years ago and I have felt no impact whatsoever. Bummer. Amino acid supplements are a bit more complicated. A diet rich in arginine has been shown in increase nitric oxide levels and decrease blood pressure, and there is some association between some of the branch-chain amino acids, like leucine, isoleucine and valine, to regulate appetite. Otherwise, most claims are unsupported.

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Washington, D.C.: Although everyone is different and has different needs, what is a decent every day supplement that the "average Joe" should take and why?

Thomas G. Sherman, Ph.D.: Personally, I advocate a good multivitamin supplemented with vitamin D and fish oil or flax seed oil. An argument can be made that women should add folate to this mix, especially if they drink alcohol. Short and sweet and fairly cheap.

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Crozet, VA: My elderly (82 and 88) parents, who don't eat especially well, swear by a "nutritional supplement" whose ingredient list I'll paste in below. I do note that its three main ingredients are water, corn syrup solids, and sugar. Is there any point in their drinking it ?

Ingredients (Vanilla): Water, corn syrup solids, sugar, milk protein concentrate, canola oil, high oleic sunflower oil,

corn oil, and less than 1% of the following: soy lecithin, carrageenan, salt, artificial flavor, vitamins (vitamin A palmitate, beta-carotene, sodium ascorbate, vitamin D 3,

vitamin E acetate, thiamin hydrochloride, riboflavin, niacinamide, vitamin B 6 hydrochloride, folic acid, choline

bitartrate, vitamin B 12, biotin, calcium pantothenate, vitamin K 1) and minerals (calcium carbonate, ferrous sulfate,

potassium iodide, magnesium phosphate, zinc sulfate, cupric sulfate, potassium citrate, potassium chloride, sodium selenite, chromic chloride, sodium molybdate, manganese

sulfate). Contains milk protein.

Thomas G. Sherman, Ph.D.: Oh my goodness! The only way to defend this cocktail, with sugar and corn syrup being the main ingredients - somewhat similar to the product label of Ensure - would be if they have difficulty maintaining their weight. I would not recommend this as a supplement to a good diet, however, and would prefer they look to other types of snacks, such as nuts or seeds, many of which are delicious and come in a broad variety of flavors and forms.

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Baltimore, Md.: I am training for a half marathon and wanted to know if there are any nutrients or foods that are particularly beneficial for long distance runners. I currently have a diet with lots of vegetables and protein.

Thomas G. Sherman, Ph.D.: Other than your great caloric requirements, your dietary needs are not that different. On the other hand, the data demonstrating the positive impact of carbohydrate loading and maintaining simple sugar ingestion during a race is surprising strong. Training increases the amount of glycogen that our livers and muscles can store, and this is a tremendous advantage during a race. Similarly, ingesting small amounts of sugar during the race helps prolong glycogen stores, because our muscles are able to take up glucose even while insulin levels are low.

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Washington, D.C.: I am wondering about the effects of fiber as a weight loss management tool. Is it merely an osmotic agent or is there evidence that diets high in fiber truly do provide a beneficial effect?

Thomas G. Sherman, Ph.D.: Fiber, along with margarine, is one of the great nutritional disappointments of the past 20 years. We recommended margarine because we were convinced that saturated fat was bad, which it is, not realizing that trans fat is far far worse. Similarly, we all thought that the increased rates of colon cancer were due to the lowered levels of fiber in the diets of industrialized countries. We all switched to those awful bran muffins for breakfast. What a waste! It is true, however, that foods rich in fiber help contribute to a feeling of fullness that will limit the intake of further calories, so in that sense, fiber aids in weight loss. More significantly, however, is obtaining your fiber from fruits and vegetables instead of carbohydrate.

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Thomas G. Sherman, Ph.D.: Studies demonstrating the effectiveness of a diet rich in fruits and vegetables in reducing blood pressure and/or LDL cholesterol, or decreasing the risks of cardiovascular disease, diabetes and some cancers, such as the DASH Study or the recently published OmniHeart Study, are in sharp contrast to recent studies on individual constituents of foods, where the results have been disappointing. Antioxidants are probably the best example of this phenomenon: foods rich in antioxidants, such as fruits and vegetables are beneficial, whereas studies of individual antioxidants, such as vitamin C, vitamin E, beta-carotene and selenium, have been largely negative. Such studies do not mean that beta-carotene, for example, is not important, but there is no reason to believe, because vegetables are rich in beta-carotene, that beta-carotene is the most important phytochemical - there are so many - and it undoubtedly is the case that it is the combination of ALL of these hundreds of phytochemicals that is what bestows the value of plant foods.

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Thomas G. Sherman, Ph.D.: Thank you all for joining me today, I have greatly enjoyed discussing this topic with you, and I apologize to the many of you who asked great questions that I was not able to get to. One great resource is a book I use in my graduate nutrition class, and that is "Eat, Drink, and Be Healthy" by Walter Willett, a Harvard epidemiologist in the School of Public Health. It is a very readable and common sense summary of recent research findings, and he does a very good job of discussing what is wrong with the USDA food pyramid, offering his own evidence-based Healthy Eating pyramid instead. My students frequently purchase a second copy of the book for their parents. Good luck to all of you as you continue this exploration of good food and healthy eating.

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