Can The Right Diet Prevent Dementia?

Written By: Sofia Layarda, MPH

Title: Master of Public Health

Alumni: University of California, Berkeley

Last Updated on:

As researchers discover many components that heal or protect our bodies in the foods we eat, there is growing interest in foods that can protect our minds. There are areas around the world where rates of dementia among the elderly are much lower than they are in the U.S. What are some dietary patterns that are beneficial and may protect against cognitive decline?

Dementia Prevention through Diet

Less Meat

A Columbia University study in 2010, published in the Archives of Neurology, followed participants living in New York and identified the following dietary pattern as being protective against the development of Alzheimer’s: higher consumption of nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark green leafy vegetables, and lower intakes of high-fat dairy, red meat, organ meat, and butter.

The residents of Okinawa, Japan have much lower rates of dementia among the elderly, even among those well into their 90s, and enjoy the longest disability-free life expectancy in the world. Dietary intake typically includes high consumption of vegetables, particularly the dark green leafy type (7 servings daily), grains, fruits, legumes and soy products, seaweed, green tea, and fish. There is very little meat or eggs in the overall diet.

More Omega-3 Fatty Acids

There’s also a link between higher consumption of omega-3-rich foods and lower risk of cognitive decline. While the optimal ratio discussed in the literature ranges from a 1:1 to 4:1 ratio (of omega-6 to omega-3 fatty acids), the typical North American has a pattern of consumption closer to a 16:1 ratio. Such high levels of omega-6 fatty acids push metabolic processes that result in pro-inflammatory substances.

Fish is one of the richest sources of omega-3 fatty acids, particularly DHA, which has been shown to protect and even competitively counter the production of omega-6 derived eicosanoids in the brains of Alzheimer’s sufferers.

Vitamins C, D, and E

Vitamins C and E are well-known antioxidant vitamins. Vitamin C is water-soluble and found in most fruits and vegetables (particularly the brightly colored ones), while Vitamin E is fat-soluble and found mostly in vegetable oils, seeds such as sunflower seeds, and nuts such as almonds. The antioxidant vitamins can help mitigate the effect of oxidative stress, that is associated with Alzheimer’s. In addition, nuts are high in monounsaturated fats, which have an inhibitory effect on many pro-inflammatory metabolic pathways in the body.

How does Vitamin D help maintain a healthy nervous system? It plays a big role in ensuring the nerves can relay messages between the brain and the rest of the body. Vitamin D also helps inhibit certain pro-inflammatory metabolic pathways. Sun exposure is a big factor in ensuring Vitamin D production among Okinawans, as they typically stay very active, and many centenarians still farm! Fatty fish, a rich source of omega-3 fatty acids, are also high in Vitamin D. Other sources of Vitamin D are mushrooms and fortified dairy products.

The Power of the B-Vitamins

The group of B-vitamins, particularly Vitamins B6, B12, and folate play an important and interconnected role in ensuring a healthy, functioning nervous system. Whole grains and legumes are high in the B-vitamins, and folate can be found in dark green leafy vegetables and citrus fruits. A 2010 study from the University of Oxford found that participants who took supplements containing Vitamins B6, B12, and folic acid lowered their blood levels of the amino acid homocysteine, which has been linked to Alzheimer’s. Another benefit of whole grains and soy products such as tofu is that they contain micronutrients such as copper and manganese, which are needed for the body’s antioxidant processes.

Phytonutrients: Antioxidant Power from Plants

Virtually all plant foods contain phytonutrients, which are potent antioxidants; some of the most familiar include lycopene, anthocyanin, lutein, and various carotenoids. Spices and herbs are increasingly studied for their antioxidant potential. In particular, turmeric – a seasoning popular in South and Southeast Asian cuisine – contains curcumin, which has been shown to activate enzymes that protect brain cells against oxidative damage, inflammation, and cell death. The green tea catechin EGCG protects neurons against oxidative damage.

The Bottom Line

The dietary patterns identified as being protective against the development of Alzheimer’s show an emphasis on minimally processed foods, mostly from plants, with unsaturated fats, particularly monounsaturated fats and omega-3 fatty acids. The focus on these antioxidant-filled foods is very much in line with the type of diet recommended for many other chronic conditions caused by too much inflammation or oxidative damage in the body, such as cardiovascular disease, diabetes, and arthritis.

While some omega-6 fatty acids are still needed in the foods we eat, most of us eat way too much. One of the quickest ways to reduce the omega-6 fatty acid levels in your diet is to cut down your reliance on most processed foods, which tend to use oils high in omega-6 fatty acids, such as corn, cottonseed, or soybean oil.

Nutrition 101

antioxidant, dha, fish, fruits, herbs, nuts, omega-3, phytonutrients, seeds, spices, vegetables, vitamins, whole grains


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