Focusing on the Nutritional Needs of Older Americans
by Richard A. Sherer| Geriatric Times |  |
July/August 2000 | |
Vol. I | |
Issue 2 |
The U.S. Department of Agriculture (USDA) has released the latest edition of Dietary Guidelines for Americans, a compendium of the latest research-driven advice for choosing foods that will promote health. Despite the fact that older Americans represent an increasingly large proportion of the population, the guidelines make few direct references to the specific needs of older adults.
"First, because it's a culmination of multiple groups that had to come to agreement, the final report tends to get watered down and be less decisive in some ways," Pamela Starke-Reed, deputy director of the National Institute of Diabetes and Digestive and Kidney Diseases, told Geriatric Times. "It's not as precise advice as you would like to hear, because there's always the matter of needing to have agreement."
"There are other reasons as well," she said. "One is that there is a lot that still needs to be determined. There is much that needs to be done in terms of elder nutrition. The take-home message is, watch what we eat and make the most healthy choices possible: fresh fruits and vegetables and fiber products (see table) food pyramid."
Dietary Guidelines for Americans is published by the USDA every five years. The guidelines are organized around the now-famous food guide pyramid, which separates categories of food into building blocks and recommends the daily number of servings in each category. For example, the base of the pyramid in the latest edition consists of the bread, cereal, rice and pasta group, and recommends between six and 11 servings from this group. In the next level of the pyramid, there are two building blocks: the vegetable group, with a recommended three to five servings, and the fruit group, with a recommended two to four servings.
Going up the pyramid, the next level also consists of two groups, each with a recommendation for two to three servings daily: the milk, yogurt and cheese group, and the meat, poultry, fish, dry beans, eggs and nuts group. At the top of the pyramid are fats, oils and sweets, with a cautionary recommendation to use these items sparingly.
The guidelines are designed as a general rule of thumb for all healthy individuals who do not need special diets, but other agencies, as well as private researchers, are now focusing attention on the special needs of the elderly.
Work is currently under way to revise the recommended daily allowances (RDAs), used by the government since the early 1940s. Information on nutrition has increased greatly since the last edition of the RDAs was published; and in the early 1990s, the food and nutrition board of the Institute of Medicine (IOM) decided to look at RDAs in a new way, particularly in light of chronic disease development. When the current project is completed, the RDAs will be replaced by dietary reference intakes (DRIs) for specific groups of nutrients. Unlike the RDAs, which used broad age categories in recommending quantities of each nutrient, the seven panels and two subcommittees of the IOM are focusing on life stage groups that define the needs of people at various times of their lives.
The RDAs made a blanket recommendation of nutritional intakes for everyone over age 55, but the new DRIs include separate recommendations for people between the ages of 51 and 70 and those who are over 70.
In an interview with GT, John W. Erdman, Ph.D., of the division of nutritional sciences at the University of Illinois said, "We carefully thought about what ages to put in there, because age is not necessarily the issue. It's mobility, activity [and so forth]." Erdman, who serves as co-vice chair of the standing committee at the IOM and was a member of the panel reviewing antioxidants, added, "One of the reasons we considered doing it differently and changing the age grouping is that we have much more data on the elderly now."
The panels based their recommendations on data gathered between 1988 and 1994 as part of the Third National Health and Nutrition Examination Survey (NHNES III) in the United States and the 1970-1972 Nutrition Canada Survey. To date, three of the projected seven reports on specific groups of nutrients have been issued.
Among the panels' recommendations, Erdman said, "For vitamin D, the recommended intake for [people] over 70 goes up from 10 micrograms to 15 micrograms. There also are some comments about the need for supplements rather than food for things like vitamin B12 because many older individuals lack the intrinsic factor to absorb B12 very well, so they probably need fortified foods and supplements to meet their B12 requirements."
In addition, there are higher recommended DRIs for calcium and vitamin D for women, who risk greater bone loss during and after menopause.
The institute's work echoes the findings released last year by Robert M. Russell, M.D., professor of nutrition at Tufts University and associate director of the Jean Mayer USDA Human Nutrition Research Center on Aging.
"We found that the pyramid being used [in the dietary guidelines] is not appropriate for elderly people, because they are not eating the serving sizes and amounts that are recommended," Russell said. "People over age 70 are leading more sedentary lives, they're not eating as much food and they're consequently taking in fewer nutrients."
Russell and his associates created a modified pyramid that takes into account the specific dietary habits and needs of people over 70 years of age (Figure). The new pyramid was published in 1999 in The Journal of Nutrition.
The Russell pyramid uses the official pyramid as its reference point, but it adds a bottom layer of eight or more servings of water. "Elderly people have a dampened thirst sensation," Russell noted, and they incur a severe risk of dehydration unless they are reminded to consume water.
At the next levels, the Russell pyramid follows the standard pyramid closely, with some variation in the recommended quantities. But at the top, Russell has added a flag that represents supplements for calcium, vitamin D and vitamin B12.
"There are a few nutrients that, even if you follow the guidelines-even ours-are problematic," Russell said. "For example, the recommendation for vitamin D is 15 micrograms, three times as much as for a young adult. That would mean you would have to drink a quart and a half of milk. An older person is not going to do that and probably can't do that. So, we recommended using supplements.
"For B12, a fairly substantial number of older people have atrophic gastritis, which means they're not putting out the same amount of acid and pepsin in the stomach. As much as 15% to 20% of people over 65 have this condition, which means they are unable to split vitamin B12 from food proteins. They can't absorb it because they can't split it off from the food complex. So we recommend a vitamin pill, which they can absorb normally. Everyone over age 60 should consider taking B12 as a supplement or as a fortified cereal product where it is sprayed on, not bound up with the food."
Russell sees the pyramid as an educational tool, designed to help seniors understand what they need to include in their diets. In his Journal of Nutrition article, he noted, "Guidance is essential regarding the selection of foods that are high in nutrient density."
Because older adults have reduced energy requirements resulting from their sedentary lives, Russell told GT, "they have to get all their nutrients in with a lesser amount of food. They need to choose foods that are more dense-that have more nutrients per calorie than [are] recommended in the classic food pyramid for adults. We're trying to stress 'nutrient dense food,' such as whole wheat grains, darkly colored fruits and vegetables, and legumes."
Russell recommended dark green, orange or yellow fresh, frozen or canned vegetables for vitamin C, folic acid, vitamin A and dietary fiber. He also noted that vegetables such as beets, kale, cabbage and broccoli contribute antioxidant phytochemicals such as indoles, flavones and isothiocyanates. For fruits, he stressed the need for whole foods rather than juices to ensure proper fiber intake.
From the dairy group, Russell recommended low-fat products and suggested lactose-free foods to overcome lactose intolerance in the elderly. For meats, he stressed the need for lean cuts and suggested that fish is a good substitute because it provides high-quality protein and fatty acids. He added, "Suggestive epidemiologic data show that fish in the diet may lower the risk of developing cardiovascular disease when eaten on at least a weekly basis." He pointed out that bean, grain and vegetable main dishes "provide high-quality protein, add fiber to the diet and...when substituted for meat, help to minimize saturated fat andcholesterol intake."
Russell cautioned against refined carbohydrates because they are "generally lower in nutrient density than the naturally occurring counterpart."
Fiber is important for the elderly as a means of preventing constipation, diverticulosis and diverticulitis, Russell said. He recommended using whole-grain breads rather than breads made with refined flour, brown rice rather than white rice, whole fruits, legumes instead of meat at least twice a week, cooked vegetables, fresh salads and "most importantly, the choice of a high-fiber cereal for breakfast."
Russell made it clear that his recommendations are intended for relatively healthy individuals, and he emphasized the need for continuous monitoring to ensure that there are no negative effects.
Russell also believes that his work is just the beginning of the process needed to refine the recommendations for elderly individuals. "Our studies are all based on the literature," he said. "They're not pretested for understanding by the older community, and we haven't done any kind of population testing on older [peoples'] abilities to follow our recommendations. We're not suggesting that the USDA adopt our findings, but we hope that this would act as a stimulus, and that they would do their own testing." The USDA's Dietary Guidelines for Americans can be downloaded from the Department of Agriculture Web site: <www.usda.gov/cnpp> or <www.health.gov/dietaryguidelines>. The IOM reports on dietary reference groups are available at <www.nap.edu>.