Eat Well, Age Well - How Our Nutrient Requirements Change as We Age
Different age groups have different energy and nutrient requirements. Typically, as we age (40, 50, 60+), our energy requirements decline due to a decrease in total energy expenditure or activity level and decreased appetite due to a decrease in our metabolic rate. Some of our nutrient requirements also change as we age due to decreased functioning of our digestive organs which compromises our ability to absorb nutrients, resulting in nutrient deficiencies. These nutrient deficiencies can lead to chronic diseases including heart disease, cancer, and osteoporosis. So, let's take a look at the different types of nutrients and how our requirements change as we age, including what foods we can eat to up our intake of certain nutrients.
MACRONUTRIENTS (protein, carbohydrates and fats)
Our required relative proportion of energy from macronutrients does not typically change as we age (protein: 10-15%, carbohydrates: 45-65%, fat: 20-35%). However, the total amount required (in grams) will likely decline due to decreased energy expenditure or lower levels of activity.
The recommended water intake for older adults (50+) is the same as it is for younger adults, about 2.7 L/day. However, the mechanisms that regulate water balance change as we age. Our sense of thirst decreases, which can lead to decrease in fluid intake, and our kidneys do not conserve water as well, resulting in increased water loss. Therefore, it is very important to drink even when you do not feel thirsty.
MICRONUTRIENTS (vitamins and minerals)
For the most part, the recommended intakes of vitamins and minerals for older adults (50+) are the same as those for younger adults. However, due to the decrease in energy intake typical of older adults, a decline in the intakes of micronutrients is common, particularly for B vitamins, vitamin D, calcium, iron, magnesium, and zinc. As well, the general function of our digestive organs reduces as we age, our digestive lining does not function as well as it used to, and we have lower amounts of stomach acid, causing a decrease in the absorption of nutrients, particularly minerals. Certain medications can also decrease the body's ability to absorb nutrients.
The following is a brief summary of the most common vitamin and mineral deficiencies in older adults and how to increase your intake through the addition of certain foods and supplements to your diet:
Vitamins B6, B12 and Folate
It is common for older adults to be deficient in vitamins B6, B12 and folate. Therefore, it is recommended that older adults consume more foods rich in B vitamins including chicken, fish, beef, pork, liver, lentils, oranges, whole grains, brown rice, legumes, spinach, sunflower seeds, soybeans, walnuts, and nutritional yeast. A vitamin B complex supplement may also be recommended (by a doctor or nutritionist), containing all B vitamins, as supplementing just one B vitamin can cause a deficiency in other B vitamins.
Vitamin D and Calcium
Vitamin D and calcium work together by ensuring a high bone density and preventing bone loss, which can ultimately lead to osteoporosis as we age. Absorption of calcium decreases with age, contributing to calcium deficiency. The Recommended Daily Allowance (RDA) for calcium for women over 50 is 1,200 mg/day, increased from 1,000 mg/day for women under 50 (1,000 mg/day for men over 50, and 1,200 mg/day over 70). As we age, our body’s ability to synthesize provitamin D when our skin is exposed to the sun is decreased, and our capacity to activate provitamin D in our kidneys also decreases. The RDA for vitamin D for women and men over 50 is 15 ug/day (20 ug/day over 70), which can be difficult to meet solely from food. Therefore, Canada’s Food Guide recommends that all adults over 50 take a daily vitamin D supplement. Foods rich in calcium and/or vitamin D that we should include more of in our diets as we age include milk, yogurt, eggs, leafy greens, cheese, legumes, fish (including the bones), sesame seeds and sunflower seeds, and fortified foods and beverages such as orange juice.
Iron needs of women decrease significantly after menopause, and the recommended iron intake for women and men over 50 is 8 mg/day. However, iron-deficiency anemia still occurs, particularly if energy intake is too low, and as a result of poor iron absorption due to lower stomach acid as we age. Therefore, we should continue to include iron-rich foods in our diets as we get older, including beef/other meats, beans, lentils, iron-fortified cereals, and dark leafy greens.
Magnesium plays a crucial role in over 300 physiological processes in our bodies, keeping the immune system strong, the heart healthy, and bones strong. Absorption of magnesium decreases as we age, and deficiency can lead to osteoporosis and cardiovascular disease. The recommended intake of magnesium for women over 50 is 320 mg/day (420 mg/day for men). Magnesium-rich foods include fresh fruits and vegetables, dark leafy greens, whole grains, nuts and seeds, beans, milk and yogurt. A magnesium supplement may also be recommended by a doctor or nutritionist.
Zinc is necessary for immune function, acid-base balance, tissue repair, and preventing premature aging. The RDA for zinc is the same for older adults as it is for younger adults (8 mg/day for women, 11 mg/day for men), but reduced absorption, physiological stress, muscle decrease, and medications can all lead to zinc deficiency as we age. Zinc from animal sources is absorbed better than zinc from plant sources, therefore, it is recommended to consume more red meat, liver, eggs, and seafood as we age.
Even though as we age we tend to need fewer calories, we need just as many or even more nutrients than we did when we were younger. For this reason, it is even more important to eat a variety of whole foods, such as fruits and vegetables, whole grains, fish and lean meats, and consider taking certain supplements (in consultation with a doctor or nutritionist) to help fight nutrient deficiencies.