A healthful diet requires a proper balance of energy, nutrients and water. While good diet habits are important for individuals of all ages, they are particularly important for older adults since diet plays a vital role in disease prevention and management. Risk factors for heart disease, the leading cause of death in older adults, are linked to diet. Type 2 diabetes, high blood pressure, Alzheimer's Disease and osteoporosis are all influenced by dietary intake.

So, just what are the unique nutritional requirements of older adults? First, as a person gets older, the body needs fewer calories. There are two reasons for this. First the basal metabolic rate (calories needed to maintain body functions such as heartbeat, digestion, breathing) decreases with age. Second, many older adults are less active as they age. The average daily caloric requirement for males over age 50 is 2300, and for females, 1900 calories. Consuming more calories than are expended can lead to overweight and obesity, both of which contribute to chronic diseases including diabetes, high blood pressure and heart disease.

Dietary carbohydrates are important sources of energy, vitamins and minerals for older adults. It is recommended that 60 percent of calories come from carbohydrates. Fiber is a type of complex carbohydrate beneficial to older adults. It can help keep bad cholesterol low, can improve blood sugar control, and is a natural laxative that relieves constipation and diverticulosis. The National Cancer Institute recommends that adults consume 20 to 35 grams of fiber per day. Average fiber consumption for older adult is much lower.

Overall fat intake for older adults should not exceed one third of total calories. More importantly, less than 10 percent of fat should come from animal sources (saturated fats). High intake of animal fats is associated with accelerated heart disease, obesity, high cholesterol and Alzheimer's Disease. Trans fats are another source of fat that should be restricted if not reduced entirely. Trans fats are found in many processed foods, bakery products and candy. Instead, "heart healthy fats" should be incorporated into the diet. Those fats include olive oil, safflower oil, sunflower oil, nuts and fatty cold water fish, such as salmon, and mackerel.

Protein requirements for older adults focus on maintaining quality protein intake while minimizing age-related bone and muscle loss (known as lean body mass). Lean body mass naturally declines with age, and illness and other stress can reduce lean body mass. The best protein sources are high quality (meat, fish, chicken) however, lean choices of meats are recommended. Three, 3-4 ounce servings of high quality protein sources should be eaten daily.

Despite a need for fewer calories, the body still needs about the same amount of important nutrients, if not more of some. Older adults can have problems getting the amounts of vitamins and minerals that they need. For example, the need for enough Vitamin D and calcium, both very important in bone health, actually increases after age 50. Yet, many older adults reduce their intake of dairy products due to lactose intolerance which increases with age. Also, older adults often reduce their time out of doors which decreases the amount of Vitamin D obtained from the sun. Older adults should get 15 minutes of sunlight at least twice a week. Good dietary sources of Vitamin D include non-fat milk, yogurt, fortified orange juice, salmon and tuna. At least 600 IU of Vitamin D3 daily recommended.

Vitamin B-6 is another nutrient that may be in short supply as we age. Vitamin B6 is important for immune system function in older individuals. One study found that the amount of vitamin B6 required to reverse immune system impairments in elderly people was more than the current recommended dietary allowance (RDA). Vitamin B6 is found in a wide variety of foods including fortified breakfast cereals, fish including salmon and tuna fish, meats such as pork and chicken, bananas, beans and peanut butter, and many vegetables will contribute to your vitamin B6 intake.

Finally, older adults are more prone to inadequate fluid intake and are at higher risk for dehydration. Persons taking medications such as laxatives and water pills should be particularly careful to drink plenty of water. Some older adults have reduced thirst sensation. At least 1.5 liters of water or non-caloric fluid daily is recommended. Total salt intake (includes sodium content of foods) should be limited.

For more information about healthy eating after age 50, visit the National Institute of Aging at Http://www.nia.nih.gov or sign up to receive Tufts Health and Nutrition Updates at http://www.tuftshealthletter.com/