Many people know that antioxidants are components of healthy foods that help boost the immune system. But, what exactly are antioxidants, how do they work and can they improve brain health?
Antioxidants are compounds found in food sources. They play an instrumental role in protecting the enzymes, fats and vitamins in the body. These natural substances help to delay or prevent certain types of damage to the cell. Brightly colored fruits and vegetables, such as those that are part of the Mediterranean diet, are a great source of antioxidants. In general, the brighter the color, the higher the level of disease-fighting antioxidants in food.
Examples of antioxidants include:
- Vitamin A
- Vitamin C
- Vitamin E
Antioxidants can be broken down into two groups including:
- Flavonoids are primarily found in plants, approximately 4,000 flavonoids have been identified. This group is broken down into seven different categories, including anthocyanidins (from blueberries, grapes and wine) and catechins/epicatechin (found in cocoa, dark chocolate and tea) and more.
- Non-flavonoids include three categories: minerals, plant pigments and vitamins. Plant pigments include carotenoids (found in orange fruits and vegetables, such as carrots and pumpkins). Vitamin C and E are the primary vitamin antioxidants. Selenium is an example of a mineral antioxidant enzyme, found in Brazil nuts, eggs, fish, grains and meat.
Antioxidants in the Body
Oxidative stress is a condition that is thought to contribute to age-related illnesses, such as Alzheimer’s disease. It results from the body’s inability to detoxify the harmful end products of metabolism (breaking down food into energy). Oxygen is required when food is burned for energy, but during that process, dangerous byproducts are produced called free radicals. As the body ages, it is not as efficient in removing free radicals, and the result is damage to the cells.
One of the most severe examples of free radical attack on the body is memory loss.
Several factors are known to speed up the production of free radicals, including excessive alcohol intake, a diet high in saturated and trans-fats and smoking. Environmental sources (such as pollution) can result in free radicals in the body as well.
Antioxidants and Brain Health
Studies have shown that antioxidants may help to counteract the unstable molecules that comprise free radicals, counteracting the negative effects of oxidative stress. Recent studies discovered that antioxidants may reverse some of the symptoms of aging (such as memory loss).
The brain uses an abundance of oxygen due to its high metabolic activity. This makes the brain more susceptible to free radical attack than just about any other area of the body. Free radical attack on brain cells results in memory loss.
Two types of flavonoids called “luteolin” and “diosmin” were shown to reduce levels of beta-amyloid (a hallmark symptom of Alzheimer’s disease) in the brain. Luteolin can be found in abundance in green peppers and tomatoes, and lemons are high in diosmin.
Studies have also shown that flavonoids called “anthocyanins” found in red berries, are associated with decreasing cardiovascular risks. What’s good for the heart is good for the brain (because cardiovascular disease increases the risk of Alzheimer’s), so, flavonoids are also highly recommended for brain health and Alzheimer’s prevention. In fact, berries are recommended daily on the Alzheimer’s Prevention diet due to the strong evidence that regular intake (a half a cup twice a week of blueberries or strawberries) was associated with delaying cognitive decline for over two years.
Top Antioxidant Foods
- Artichoke (boiled)
- Citrus fruit
- Dark chocolate
- Ginger and turmeric
- Goji berries
- Green tea
- Kidney beans
- Wild blackberries, blueberries, raspberries, strawberries
Many studies have also been done on the effects of cocoa powder flavonoids on memory loss. Flavonoids from cocoa were found in clinical research studies to inhibit the death of neurons by interfering with free radicals in the brain. The primary flavonoid in cocoa and chocolate is called epicatechin, which was found to improve cognitive function in animals and humans. In rat studies, flavonoids from cocoa and chocolate were found to preserve cognitive abilities. Human studies discovered that cocoa flavonoids lowered the risk of developing Alzheimer’s disease and stroke.
A 2012 study of people with mild cognitive impairment (MCI) who drank a specific type of cocoa drink, called Cocoa Via, resulted in significant improvement memory function in study participants. It’s important to note that many of the flavonoids are removed when most brands of cocoa are processed from its raw form and that the study involved a particular type of pure, unsweetened cocoa, called CocoaVia.
Resveratrol is part of a group of compounds that act like antioxidants, called polyphenols. Resveratrol is thought to protect the body against damage that can increase the risk of diseases, such as cancer and heart disease. Resveratrol is found in the skin of red grapes, so it’s abundant in blueberries, cocoa powder, cranberries, grape juice, peanuts and wine. Some preliminary animal studies have shown that resveratrol helped to delay cognitive decline, but human studies are somewhat limited. One study did, however, discover that memory function improved in people with mild to moderate Alzheimer’s disease who took supplemental resveratrol.
Have you incorporated antioxidants into your diet to improve your brain health? We’d like to hear more about your Alzheimer’s diet in the comments below.