Nutrition and Alzheimer’s disease
Gaye Philpott is a registered dietitian who has practiced in and around Palmerston North for the past 16 years. She writes a regularly nutrition column for Alzheimers News and INsite magazine and also assists Alzheimers New Zealand with information about diet and nutrition for people with dementia. Gaye works one-on-one with individuals and families in her practice, Nutrition Matters and is the chairperson of Dietitians NZ’s Special Interest Group for Nutrition of Older Adults. Below is an article Gaye wrote for the September 2010 edition of Alzheimers News.
Alzheimer’s is such an emotive disease. For those watching and caring for loved ones with this condition, it can be heartbreaking. For those who are themselves experiencing the early stages, or who know they have a strong family history of the disease, it can be very scary. And with no known cure and limited treatment options we are greedy to find ways and means to reduce the risk of this disease and minimise its progress.
Food too is an emotive subject. We all have personal beliefs about nutrition and how it affects our health and well-being. These beliefs may be based on personal experience, what our family and friends tell us, or what we read. We may choose to adapt our food and nutrient intake based on what we believe.
For health professionals, before they can make specific recommendations for someone’s diet, they need proof that what they recommend will have the effect they say it will, but without causing other detrimental outcomes. This is referred to as evidence-based practice and is reliant on a robust scientific process.
Alzheimer’s disease is a condition of the brain where the cells (neurons) degenerate and no longer function as effectively as they once did. It is also a progressive disease which means brain function continues to deteriorate over time. Both genetics and environmental factors influence its onset and progression.
So how might food and its nutrients affect Alzheimer’s disease? Food is an environmental factor and there are several mechanisms by which it might influence this condition.
It is possible that a lack of some nutrients might be responsible. Studies have found that low levels of some nutrients specifically associated with cognitive loss do occur in people with Alzheimer’s disease. However, what yet needs to be proven is that reversing these deficiencies prevents the onset or halts the progression of this condition. Research has not yet shown this.
Consuming extra amounts of specific nutrients could also have a protective effect on brain health. Because Alzheimer’s disease affects older rather than younger people, it has been proposed that the oxidative and inflammatory stress of the aging process may be responsible for the degeneration of brain cells. A number of animal and laboratory studies have shown that antioxidant nutrients (vitamins C and E and beta-carotene) and omega-3 fatty acids (a polyunsaturated fatty acid) can protect the brain from such damage, but as yet there is insufficient data from human studies to back these claims.
Some of you reading this article may well be thinking there is surely no harm in taking supplement doses of these ‘goodies’. And in regard to omega-3 this would be fair comment. However, research cautions the use of supplement doses of anti-oxidants, as detrimental effects such as increased rates of some cancers have been observed. This is not to say that the antioxidant nutrients don’t play an important role in health, just that it is better when they are consumed in the amounts present in a healthy diet.
So while specific nutrients in food show promise in counteracting the effects of aging by promoting brain health, there is not yet sufficient evidence to recommend supplement doses of specific nutrients or special dietary treatments for those with or at risk of Alzheimer’s disease.
Until there is, this message remains: eat a healthy diet low in animal fats, but including plant based oils. Include wholegr
ain breads and cereals rather than refined versions and at least five servings of fruit and vegetables daily. Eat at least two servings of foods made from milk daily (preferably reduced fat choices) and one to two servings of foods from the meat group, including fish once or twice per week.
