Successful aging starts with a balanced diet

Zoomer | April 1st, 2000

It’s becoming increasingly clear that our lifestyle choices are a major determinant of health, and diet and nutrition choices are among the most important of these factors. Unfortunately, many people do not appreciate that as we age it’s more important than ever to eat well. But poor nutrition is not just an issue for seniors; the diet of adults in middle age is important as well. Good nutrition is cumulative – we’re not just what we eat – we are what we ate.

Why do seniors suffer more from nutritional inadequacies than other age groups? For one thing, as we age there’s reduced absorption and less efficient utilisation of nutrients by our bodies. In addition, many seniors experience decreased food intake because caloric requirements are lower. For some, difficulties with cooking or shopping raise obstacles, while others experience a declining sense of taste – often exacerbated by the effects of medications or illness — making eating less pleasurable than it once was. As a result of these and other factors, seniors need to be particularly careful about obtaining adequate nutrients in their diets.

The importance of good nutrition is evide in a variety of areas. Among the links explored in this edition of Baycrest Report on Healthy Aging are those between diet and mental abilities, disease prevention, and osteoporosis.

Nutrition and Mental Ability
Important new research at Baycrest Centre for Geriatric Care clearly suggests a link between nutrition and cognitive decline with age. It’s been known for many years that deficiencies in several key nutrients was associated with lower levels of cognitive performance – including tests of memory — in otherwise healthy seniors, even if signs of malnutrition were not evident. These types of nutritional deficiencies are indicative of diets low in fruits and vegetables and high in cholesterol, monounsaturated and saturated fatty acids. (This is the same profile of poor nutrition that is associated with higher risk of disease, as discussed below.)

The key nutrients associated with cognitive performance are riboflavin (vitamin B₂), ascorbate (vitamin C), folate (folic acid) and Vitamin B_12.Inaddition, there are cognitive benefits associated with antioxidant intakes, in particular past (but not current) intake of Vitamin E. It’s important to recognise that seemingly adequate diets may not provide sufficient amounts of these nutrients. In fact, recommended levels of folic acid are currently under review with an eye toward increasing them. So be aware that your current levels of nutrients might not be adequate and could contribute – if only in a small way – to cognitive decline.

Other factors
These proposed links between diet and cognitive function could be due to other factors, including smoking, alcohol consumption, and stress. For example, high levels of stress could lead to poor diet, high risk for cardio-vascular disease, and poor cognitive performance. Because research with humans makes it difficult to untangle these factors – scientists cannot and will not deliberately expose groups of people to stress in order to measure the impact on diet and memory – we must turn to studies using animals.

Drs. Carol Greenwood and Gordon Winocur of Baycrest Centre for Geriatric Care found that adult rats fed a diet high in fat for three months developed cognitive impairments. Conversely, studies of rats fed reduced calorie diets demonstrated reduced levels of cognitive decline.

If we look at the animal and human studies together, we see considerable evidence that poor diet is indeed a factor associated with cognitive decline – as well as other deficits, which we will see shortly.

While these studies have emphasised the long-term implications of poor diet, the immediate diet can also influence brain function. Water soluble vitamins, because they’re not stored in the body as readily as fat soluble vitamins, are especially important. So an important lesson to bear in mind is that good nutrition must be an on-going concern. A proper diet, with adequate amounts of key nutrients, is a good investment in your long-term well-being.

Scotiabank is committed to helping provide Canadians the tools they need to enjoy health and well-being as they age. We are proud to fund this innovative report. Congratulations to Baycrest on your vision and leadership.

Nutrition and Risk for Disease
Poor dietary practices in adults also increase the risk for disease, including cardiovascular disease and non-insulin dependent diabetes mellitus (also known as mature-onset or type II diabetes).

A recent study in the Journal of the American Medical Association reported that people who consumed at least five servings of fruits and vegetables daily were at more than 30 per cent lower risk of having a stroke compared with those who consumed minimal amounts of fruits and vegetables. Among the best candidates for consumption – vegetables in the cabbage family (which includes broccoli, cauliflower, and bok choy), green leafy vegetables, and citrus fruits and juices.

Type II Diabetes is also associated with poorer cognitive performance. On the one hand, it is encouraging that proper treatment of diabetes can lead to improved cognitive functioning. But on the other hand, even before diabetes can be diagnosed cognitive decline may be evident at early stages of insulin resistance. So can diet make a difference for those who may be in the early stages of insulin resistance and have not yet been treated for diabetes? Baycrest scientists Greenwood and Winocur have recently shown that glucose consumption – in the form of mashed potatoes and barley — led to improved memory function in elderly study participants. What does this mean?

“Glucose fuels the brain but, as the brain ages, its capacity to absorb glucose decreases,” says Dr. Winocur. “We can assist this critical function by including, in our diets, complex carbohydrates, like starches, that provide the brain with a constant supply of this essential nutrient.”

Steps you can take to improve nutrition
The type of evidence reviewed so far strongly suggests that you make every effort to boost your intake of essential nutrients. But even good diets can lack enough of these nutrients. So are vitamin and mineral supplements useful? It’s difficult to determine for certain, because those seniors who take supplements also tend to have better dietary habits. However, given that the recommendations for intake of several key nutrients is being raised it’s very possible that many seniors are not getting all they need from diet alone. Thus, Drs. Greenwood and Winocur recommend a supplement, but caution that this alone is not sufficient to overcome the negative effects of a poor diet.

Fortunately, not all seniors are at risk of malnutrition. Those most at risk have the following characteristics: underlying diseases, living in isolation, living independently, below the poverty line, and those taking multiple medications.

But it’s important to remember that good nutrition is not something that one can “turn on” for one’s 60th or 70th birthday. It’s important to develop and maintain good nutrition throughout adulthood. If you’re a new reader of CARPNews FiftyPlus, there’s no better time to start than right now!