If you feel your memory isn't as sharp as it used to be, the remedy might be no farther away than your refrigerator. According to two new studies, the foods you eat – and supplements you take – can boost your brain power.
The first study, published in the journal Neurology, analyzed the diets of 17,478 men and women with an average age of 64 to see how closely they adhered to the Mediterranean diet. The participants did not have any memory impairment at the start of the study and underwent cognitive tests annually over a four-year period.
The Mediterranean diet is a pattern of eating that is low in saturated fat, high in heart-healthy monounsaturated fat and plentiful in vitamins, minerals and antioxidants. It's primarily plant-based, with fruits, vegetables, whole grains, legumes and nuts eaten daily.
The study found that closely following the Mediterranean diet was associated with a 19-per-cent lower likelihood of developing memory and cognitive problems. It's thought that the combination of healthy foods in the Mediterranean diet protects the brain by keeping blood vessels healthy.
Risk factors that damage blood vessels – high cholesterol, hypertension and high blood sugar – are also risk factors for cognitive impairment and Alzheimer's disease. (Previous research has also linked the Mediterranean diet to a lower risk of Alzheimer's disease.)
There was no link, however, between the Mediterranean diet and memory among people with diabetes. There is recent evidence that diabetes may damage cognitive function in additional ways unrelated to vascular health.
For the second study, a randomized controlled trial, New Zealand researchers tested whether supplements of DHA (docosahexaenoic acid) – an omega-3 fatty acid found in oily fish – could improve memory in 228 healthy young adults, aged 18 to 45, who ate only small amounts of oily fish.
DHA is the dominant omega-3 fat in the brain where it helps keep the lining of brain cells flexible so memory messages can pass easily between cells. DHA is also thought to prevent the build-up of a protein called beta amyloid, which can interfere with communication between brain cells.
The six-month study showed, for the first time, that young adults who took a daily 1.2-gram DHA supplement – equivalent to eating three ounces of salmon or six ounces of trout each day – had improved memory and reaction time compared with those who were given a placebo.
Past studies conducted in older adults have linked higher intakes of fish and higher blood levels of omega-3 fats with a lower risk of dementia, slower brain aging and better memory.
More and more we're learning that certain foods can help you concentrate, stay motivated, improve your memory and protect against age-related cognitive decline. Research suggests the following foods belong in a brain-friendly diet:
Adopt a Mediterranean-style diet
Make fruit and vegetables part of your daily diet; aim for two to three fruit servings (e.g. one medium-sized fruit) and at least five vegetable servings (e.g. 1/2cup cooked or raw or 1 cup salad greens) per day.
Limit red meat to three times per month and keep portion size to four ounces. Include fish and poultry more often. Eat legume-based meals a few times each week; try lentil soup, chickpeas in a salad, vegetarian chili or black bean tacos.
Use olive oil, rich in monounsaturated fat, as your principal source of fat.
Include oily fish such as salmon, trout, Arctic char, herring and sardines in your diet twice a week to increase your intake of DHA. (These fish are also low in mercury.) Enjoy fish baked, grilled or steamed.
If you don't like fish – or you eat it infrequently – consider taking fish oil in capsule or liquid form. Note, though, that fish liver oil capsules are typically not a good source of omega-3 fatty acids. Long-term intake of fish liver oil may lead to toxicity because of high amounts of vitamin A.
Blueberries, blackberries, strawberries and raspberries contain polyphenols, natural compounds thought to protect brain cells by fighting free-radical damage, reducing inflammation and clearing toxic proteins that accumulate with age.
Other polyphenol-rich fruit include acai berries, cherries, cranberries, plums, pomegranate seeds, prunes and red and purple grapes.
Get your greens
A daily intake of leafy green vegetables such as kale, arugula, Swiss chard, collard greens, rapini, Romaine lettuce and spinach has been shown to slow the rate of cognitive decline in older adults.
Researchers believe the protective effect of leafy greens is due to vitamin E, an antioxidant that protects brain cells from oxidative damage and inflammation.
Include at least one serving (1/2 cup of cooked greens or 1 cup of salad greens) in your daily diet. Cooked greens contain more antioxidants than raw.
Choose unsaturated fats
Limit your intake of foods high in saturated (animal) fat such as butter, cream, cheese and fatty meats. Higher intakes of saturated fat have been linked to a greater risk of Alzheimer's disease.
Prepare foods with unsaturated fats such as olive, canola, peanut and grape-seed oils. To increase your intake of monounsaturated fat include almonds, cashews, hazelnuts and avocado in your diet.
Leslie Beck, a registered dietitian, is the national director of nutrition at BodyScience Medical. She can be seen Thursdays at noon on CTV News Channel's Direct. Lesliebeck.com