Protein and Amino Acids, 1997
Pp. 341-346. Washington, D.C.
National Academy Press
ROBERT NESHEIM: I would like to open the session for a general discussion. Gail?
GAlL BUTTERFIELD: Alana (Cline), did you have an actual measure of protein intake in the women who responded to your survey?
ALANA CLINE: No, we don't have an actual number of grams of protein, but we have the information on food category intake, so we will be able to take a look at that. Again, we are still compiling the data.
GAIL BUTTERFIELD: Do you have a caloric intake yet?
ALANA CLINE: No.
GAIL BUTTERFIELD: Okay. The reason I asked is, it is very clear from all the presentations, that we have very little information on protein requirements in women, and I suspect from work that I have done with female athletes that in fact women as a group may be somewhat at risk for inadequate intakes. So it would be interesting to see what the protein and energy intakes were for the female soldiers.
ALANA CLINE: We do have data available from the study we did at Fort Sam Houston on iron deficiency in women, so we do have some data from women's studies.
PARTICIPANT: And we are planning a field study in which we will have a significantly larger women's population than we have had in the past, too. That will be done in April and May.
ROBERT NESHEIM: Any other questions? Yes?
DOUGLAS WILMORE: A question for Harris Lieberman and for Karl Friedl. We have heard some really fairly simple and practical strategies about repletion of muscle glycogen. In practice, in Ranger training, are any of those strategies utilized at all, for example, carbohydrate loading, with or without protein, at the end of a march or at the end of an exercise period?
KARL FRIEDL [off microphone]: It is not used in Ranger training. The point there is to create this energy deficit as one of the deliberate stressors. That is their training strategy.
We have a new carbohydrate drink that has just been fielded, and maybe Pat Dunne can talk about that, a maltodextran drink, which was really the result some of the field studies done by ARIEM, and they finally recommended that it get type-classified. Actually, the USARIEM folks and the Natick folks have been ahead of the game there. The product is already available.
So there is at least a carbohydrate supplement, an energy supplement, which, in some of the Pennington studies of Special Forces soldiers on the treadmill, was shown to enhance and prolong the endurance time by 15 percent when soldiers received the supplement during exercise.
DOUGLAS WILMORE [off microphone]: We have examined the effects of protein supplements, but didn't consider using potassium, sodium, and some of the other factors.
ANTON WAGENMAKERS [off microphone]: Why do you deliberately conduct training in a state of energy deficiency [inaudible]?
KARL FRIEDL: Oh, that's a long story that we will have to talk about over dinner.
ROBERT NESHEIM: Jim?
JAMES HODGDON: I just wanted to respond to the question. We currently have a program, and I suspect more people in the Navy are interested in studying this. We have been working with a group at Yale so that we can use the magnet to measure the amount of glycogen in the muscles rather than doing biopsies, so we have the opportunity to look at depletion rates.
DOUGLAS WILMORE: Have you looked at possible additions?
JAMES HODGDON: No. We will now, I think, since that issue has been raised.
PARTICIPANT: We are doing that.
ROBERT NESHEIM: John?
JOHN VANDERVEEN: We didn't really address the issue of long-term health and protein quality today, but one of the questions we had asked in planning this was, is there any benefit from changing protein sources? There is some literature out there, and maybe someone would like to address the issue of animal versus plant proteins relative to lipids and cardiovascular disease and perhaps other conditions. There was a little discussion, perhaps, of the benefit of phytoestrogens and so forth. But is there anyone who wants to address or talk about that area?
DOUGLAS WILMORE: I will just start the discussion. You can change animal protein for soy or a vegetable protein mix on a gram for gram basis and keep the fat contents the same in the diet and observe lipid-lowering effects. There is a fair amount of epidemiology supporting the belief that these effects and the phytoestrogen effects may be the reason you can get protection for prostate
cancer in men and for breast cancer in women as you move over to plant protein sources.
It is also why you don't see perimenopausal symptoms in Asian cultures where soy protein is the dominant protein source, because prior to menopause, the exogenous estrogens from food sources block some of the endogenous estrogen effects, and during the postmenopausal period, exogenous estrogen is still stimulating those receptors, so estrogen withdrawal is not a major factor. So there is a growing amount of evidence that would suggest that long-term health effects are improved with vegetable, particularly soy, protein sources.
D. JOE MILLWARD: Can I just add one comment to that? As was just shown to us, the principal phytoestrogens from soy are genestein and daidzein, and certainly those compounds have been quite intensively investigated now.
But the lignins, which come from other plant sources, also have phytoestrogen effects, and actually, the intake of lignins is higher than that of some phytoestrogens. Of course, there are lots of societies where soya is not a normal part of the diet but the vegetarian background of the diet involves high intakes of lignins.
So I think that the phytoestrogen story is something that is spreading from soya right across the spectrum, and in many ways the key issues of plant versus animal protein may well reflect this issue of other travelers (as yet unidentified compounds). It is a complicated issue, because the micronutrient bioavailability is high from animal protein and low from plant protein sources. But these other phytoprotectants in plants are not present in animal protein, so it is quite a complicated issue. Thus it is probably that phyto protectant element that is important rather than the amine acid issue.
DOUGLAS WILMORE: And you cannot substitute these things with vitamin pills. That is the other thing that society must learn. You know, you've got to eat your spinach if you want to preserve your eyes and your late vision. You cannot take a vitamin pill and preserve that, and that has actually been shown.
The most common operations done in the United States are cataract operations, and if you take the people over 65 and divide them into quartiles, the people who eat five or more vegetables a day have an incidence of cataract surgery of 5 percent or less, and the people who eat zero to one helping a day have an incidence of cataract surgery of something like 25 or 30 percent. This is presumably preventable through long-term nutrition.
ROBERT NESHEIM: There are some interesting studies. There was the three-country study that was conducted in Mexico, Kenya, and Egypt, looking at the effect of diet on infants, toddlers, and so on.
One of the results of that study that was rather interesting was that they found that among those young toddlers and school children, the ones who got some animal protein in their diet actually had better cognitive performance and better growth than did those who were not getting that. It was probably related to B 12 for one thing—at least that was one of the hypotheses, which could be more important in certain stages than others. I only mention that because I don't think we are ever going to get to a totally vegetarian diet devoid of B 12 sources in this country, but there is a balance of all these factors that needs to be looked at in the total population. Yes?
RICK LEVINE: In line with the idea that Dr. Wilmore discussed, supplements versus foods, he previously had talked about antioxidants and supplementation. Should we also be looking at high sources of antioxidant foods to be incorporating those into operational rations as opposed to looking at supplemental sources?
DOUGLAS WILMORE: That might be ideal. Clearly, what would be ideal would be to genetically manipulate plant protein so that we would have a highglutamine plant protein source, for example, or a profile of amino acids that would be more desirable for certain kinds of conditions. The iron issue that Wanda raised is a very timely issue, particularly because iron supplementation is now being carried out, I think, in a number of women because of anemia.
So I think it is a desirable goal to consider food sources of nutrients. My concern has always been those periods of time when people don't eat enough, and I have always had concern, and have concern now, about the recommendations that we have in our notebooks about people going out on 10-day missions with inadequate diets, and those diets are inadequate across the board. What concerns me is that there may be very small, lightweight supplements that might give soldiers some additional protection.
KARL FRIEDL: That is a reasonable point, too, because we have a new generation survival ration.
PARTICIPANT: Actually, the LRPR (Long-Range Patrol Ration) would be the one you mean.
KARL FRIEDL: Yes, the LRPR.
ROBERT NESHEIM: There is a concern with survival rations containing too much protein. Extra protein increases the requirement for water, which may be limited in a situation where survival rations are needed.
We issued a report not too long ago on the subject of not eating enough, and in that report the committee made a strong recommendation that, just as the military has a water doctrine, there ought to be a food doctrine; in other words, that soldiers and military personnel should be educated to understand that food is the fuel that runs them, just as diesel is the fuel that runs their motorized equipment, and that they need to be aware of the potential adverse effects of energy deficits in the field.
Now, we know there are a lot of things that contribute to why soldiers don't eat enough. I am sure that any of us, in a similarly stressful situation, would find ourselves not wanting to eat or not being in a position to eat even though we know that we are supposed to eat. But I think the emphasis on a food doctrine is important, just as it is on a water doctrine, and I think we probably need to continue to emphasize that.
ROBERT NESHEIM: I think we have had a full day, a very full day. I just wanted to thank all of the speakers for their fine contributions. I think we have had an excellent day. The speakers made interesting presentations. They were pretty well on target all the way through. We had good discussion, and you have presented our committee with a lot of challenges in terms of writing a report.
I do want to urge the speakers to get your papers to us, because we are under a real tight constraint in trying to get a report completed within the time frame of what we are committed to doing. So please help us out by getting papers to us as quick as you can if you haven't got it done already.
So I just wanted to close this by thanking all of you for your participation in this particular meeting. I appreciate all our visitors, military and civilian, that are with us, and I hope that you have had an enjoyable day of listening to all of this particular presentation. You have put some real challenges to us as a committee, to try to come up with some recommendations and some meaningful input to the military.
HARRIS LIEBERMAN: Okay. Bob, I cannot even begin to convey it, but I wanted to thank you for the tremendous contribution that you have made to the Committee on Military Nutrition, to the health of soldiers, to the advancement of the science of military nutrition in your many years as the leader of the Committee on Military Nutrition Research. So thank you very much.
ROBERT NESHEIM: Thank you, Harris. It could not have happened without the input of all of the people on the committee and all of the speakers who have presented data to us so we were able to get it together. So it has been great.