Our bodies change as we age – partly due to natural physiological aging and partly due to lifestyle choices. As early as our thirties, we begin to lose a small amount of muscle mass, and, as we get into our sixties and seventies, this process (known as sarcopenia) speeds up and by then we may have lost up to half of our muscle mass. (If you implement strength training under the care of a professional, you can regain some of the loss.)
Our vital organs also change; for example, according to Dr. Heather Keller, a professor in the Department of Kinesiology at the University of Waterloo and a Schlegel Research Chair in Nutrition and Aging with the Schlegel-University of Waterloo Research Institute for Aging, our skin “thins and the fat layer below the skin changes as well.” Theories about changes in our kidneys include that they lose some of their function due to use over time or because of a “free radical build-up issue.” Free radicals damage cells in the body and may also contribute to the formation of cancer.
But one of the most significant changes as we age is to our endocrine system (our hormones), says Dr. Keller. For women, menopause means a decrease in levels of estrogen and progesterone. For men, many over the age of sixty will experience some testosterone loss. For both sexes, there is a chance that thyroid function will decline. Notably, the body’s ability to make or process insulin can change as well. “We tend to get more insulin-resistant as we get older,” says Dr. Keller. Risk for disease increases, and scientists are still exploring why aging often leads to illness.
With all of these bodily changes due to age, paying closer attention to our diets becomes even more critical as the years pass. Because of the muscle loss, and the fact that we tend to move less as we age, older individuals need to consume fewer calories than their younger counterparts. Muscles are a big driver of our energy consumption in the body, says Dr. Keller. Additionally, “we lose muscle and gain fat, even if our weight remains stable,” says Dr. Alice H. Lichtenstein, senior scientist and director of the Cardiovascular Nutrition Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. This change means that “older adults need to eat fewer calories, yet get the same amount of nutrients as younger adults,” she adds.
To achieve this, older adults need to be “more careful about food choices,” says Dr. Lichtenstein. Choosing “nutrient-dense” foods – those with a high number of vitamins and/or minerals per calorie – needs to be a priority. At the grocery store, look at the “colour of the flesh” of the fruits and vegetables you are purchasing – the more deeply coloured, the higher the nutrient density. For instance, consider buying kale, chard, and romaine over iceberg lettuce, or adding berries and other colours of fruits to your apples and pears.
“Another helpful shift is from full-fat to low-fat dairy products,” says Dr. Lichtenstein, so that you still get the nutrients that you need, but are consuming fewer calories. Adding more fibre to your diet is also important to keep your gut from becoming sluggish. Choose whole grain breads and pasta instead of white, and eat whole fruit instead of drinking fruit juice.
To be efficient at creating new muscle as we age, we need to consume more protein. Twenty to thirty grams of protein at every meal is important, according to Dr. Keller. Foods such as low-fat milk, Greek yogurt, and skinless chicken are all good sources of protein without being too high in fat. It is also important to try to balance out your protein consumption over the course of the day, as opposed to consuming one big steak at suppertime. You can incorporate plant proteins as well, says Dr. Keller, but there is a challenge for older adults: beans, for instance, are not an efficient source of protein because you need a lot more of them in order to satisfy your protein requirement (which means that you will be eating more calories).
Because of the skin and kidney changes that occur as we age, we need to be extra careful about our vitamin D levels. “We get a preform vitamin D from the sun,” explains Dr. Keller, “and then the kidneys change it into something our body can use.” However, since both the skin and the kidneys lose some functionality as we age, it becomes increasingly important to take vitamin D supplements in order to achieve sufficient levels of this essential vitamin. Our bodies need vitamin D in order to absorb calcium, which means osteoporosis risk increases when levels of both calcium and vitamin D are low.
“Other micronutrients are not as well studied, unfortunately,” says Dr. Keller. Antioxidants in general are getting more attention because of their ability to fight free radicals. Berries and orange vegetables (such as sweet potato), as well as dark, leafy greens, are high in antioxidants. Supplementation with antioxidants has not shown promising results in early studies, so it is best to get your antioxidants from food sources.
In general, while there has been an increased focus on nutrition in recent years, “it’s often driven by weight instead of health,” observes Dr. Keller. What diets such as the “MIND” diet or the “FINGER” diet (similar to the Mediterranean diet) – recommended for Alzheimer’s disease or dementia prevention – or the “DASH” diet – recommended for healthy blood pressure – have in common, says Dr. Keller, is “a healthy, wholesome diet.”
The “yo-yo” dieting that many young adults participate in can be detrimental as they age. “It resets the body at a lower level of what we need for energy, so we’re setting ourselves up for failure,” says Dr. Keller. We should instead be asking ourselves “are we eating well, are we feeling well, and are we moving well,” notes Dr. Keller. Reducing our intake of good quality food and protein in our fifties and sixties in order to lose a few pounds (for instance, eating a salad without chicken or toast instead of a cooked meal with a variety of vegetables), can contribute to overall poor health as we age. It might be best to forget about the scale and focus on nutrition for our long-term health.
Another consideration as we age is nutrition risk and malnutrition, which is an under-diagnosed issue with older adults, says Dr. Keller. According to a paper published in Advances in Nutrition, adults over the age of sixty-five are more prone to nutritional deficiencies, which, on the biological side, is due to some of the bodily changes previously mentioned, as well as the fact that an older body can have difficulty absorbing certain nutrients.
The social reasons for the malnutrition risk, though, can be more challenging to conquer. As we age, we tend to eat less with others. “Family has moved away or a spouse may have died and cooking might not be a priority anymore,” says Dr. Keller. Taking a trip to the grocery store becomes difficult in the winter months, for instance, due to fears around falling, so individuals “will live on what they have in the house” or just purchase a few items at a corner store, which often do not sell perishable foods.
All of these factors contribute to an older person’s diet becoming poor, and, over time, can lead to frailty. It is important to understand, though, that your nutrition – especially when older – impacts your independence. “Maintaining a quality diet that is rich in micronutrients, sufficient protein, and balancing calories with their energy output is really important for people to stay independent for as long as they can,” says Dr. Keller.
We now know that diet can be preventative when it comes to Alzheimer’s disease and dementia. An antioxidant-rich diet (such as the “MIND” or “DASH” diet) might even slow dementia progression once an individual is already diagnosed, says Dr. Keller. Never underestimate just how important it is to your long-term health to trade in the empty calories for a wide variety of micronutrient-rich foods, low-fat proteins, and good fats as you age.
In 2016, Dr. Alice H. Lichtenstein and her colleagues at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University released an updated MyPlate for Older Adults, which provides food, fluid, and physical activity guidance specifically tailored for older adults. MyPlate emphasizes the importance of consuming fruits and vegetables (which includes frozen and canned products that have a longer shelf life for those who cannot get out to the grocery store as often), low-sodium meals, and lean protein. For more information, visit https://hnrca.tufts.edu/myplate/.
Dr. Heather Keller, in collaboration with the Dieticians of Canada, developed an online tool in 2012 called Nutri-eScreen, which assesses older adults’ appetite, eating habits, and changes in weight to identify those who may be at nutritional risk. The tool involves 14 short questions about eating habits and takes approximately ten minutes to complete. Upon completion of the questionnaire, users will receive recommendations for improvement based on the responses provided. For more information, visit http://www.nutritionscreen.ca/escreen/default.aspx.