Brain Health News Update 2020
Written by Annie Fenn, M.D.
While the novel coronavirus pandemic has dominated science news in 2020, there have also been important advances in brain health. Researchers tackled key questions like: What are the most important modifiable risk factors for Alzheimer’s? How does one mitigate the impact of pollution on brain health? And, what is it that makes fruits and vegetables so good for long term brain health?
Here, I share three studies that are key to understanding how to protect your brain from age-related cognitive decline and my real-life strategies for putting them in place in your life. Things like boosting your intake of flavonol-rich foods, combating the effects of air pollution, and understanding risk factors will help you cultivate a healthier brain now, and for decades to come.
Flavonols are the reason fruits and vegetables are so good for the brain.
Kaempferol, isorhamnetin, and myricetin may not be household names, but these are all types of flavonols, a family of compounds found in vegetables and fruits. Flavonols have been nutrients of interest for brain health due to their potent anti-inflammatory, antioxidant, and vasodilatory effects. In other words, they combat the aging process by enhancing blood flow and blocking inflammation in the brain.
Every dietary pattern proven to fend off Alzheimer’s includes an abundance of vegetables and fruits. In the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet1, for example, leafy greens, other vegetables, and berries make up three of the ten brain-healthy food groups demonstrated to reduce Alzheimer’s risk by as much as 53%.
For the first time, the dietary flavonols found in these plants have been linked to a significantly lower risk of developing Alzheimer disease. In a study published in April of this year in the journal Neurology,2 Rush University investigators found that those participants who reported diets highest in flavonols had up to 48% lower risk of developing Alzheimer’s when compared to those who consumed the lowest levels of these dietary compounds. They proved this by following 921 dementia-free adults (75% of whom were women) with annual neurological examinations and detailed dietary questionnaires over six years.
The careful design and follow-up of this prospective study shows what the scientific literature has been hinting at for decades: eating more foods rich in plant nutrients from the flavonol family translates to a lower risk of Alzheimer’s disease later.
Kaempferol—the flavonol found in leafy green vegetables, beans, tea, and broccoli—proved to have the strongest association with protecting the brain from Alzheimer’s, with a 48% risk reduction. Myricetin, found in kale, pears, olive oil, oranges, tomatoes, and red wine, was associated with a 38% risk reduction. And those participants who ate more foods rich in isorhamnetin, found in tomatoes, kale, apples, and tea, also demonstrated 38% fewer cases of Alzheimer’s.
Study participants with the greatest reduction in Alzheimer’s risk consumed on average nineteen cups of tea (black or green), eight apples or pears, and seven cups of blueberries or strawberries each month.
Take-Away for Brain Health: This study makes a strong case for including an apple (or pear) a day in your brain-healthy diet. Be sure to enjoy plenty of other flavonol-rich foods, too: leafy greens (kale, spinach, lettuces), tea (black or green tea for the highest concentration of kaempferol and myricetin), broccoli, onions, oranges, and berries. Cooking tomatoes, as in a marinara sauce or soup, actually enhances your body’s ability to absorb their flavonols. Red wine, although rich in flavonols, is best enjoyed in small amounts—no more than five ounces per day.
Modifiable Risk Factors for Alzheimer’s Updated by Lancet Commission
Key factors like controlling blood pressure, correcting hearing loss, and limiting alcohol may help reduce your risk of Alzheimer’s.
Adapted from Livingston, G., Huntley, J., Sommerlad, A., et al., Lancet, 2020.3
It’s very common to have one or more risk factors for Alzheimer’s disease. For some, this may be a family history, like having a mom, sister, or brother with the disease. (While most cases of Alzheimer’s are not hereditary, some families do carry a risk gene, like APOE4, that heightens risk.) For others, it may be a personal health condition, like diabetes or high blood pressure.
As it turns out, most of the cases of Alzheimer’s disease in the world today fall under the “modifiable” category, meaning you can take measures to change them. These are the factors related to health, environment, and dietary patterns.
The Lancet Commission, a symposium of the world’s leading Alzheimer’s experts, divides these into early life (lack of childhood education), mid-life (hypertension, obesity, hearing loss), and later life factors (smoking, depression, physical inactivity, social isolation, diabetes.) They estimate 40% of the world’s Alzheimer’s cases could be eliminated by reducing these risk factors. With 152 million people expected to be living with Alzheimer’s by 2050, this is a staggering number of brains that could be saved with this proactive approach.
That’s why when the Commission updated its landmark 2017 study (published in the journal Lancet in August, 2020 Lancet Commission Report on Dementia, Prevention, Intervention and Care)3 by adding three more modifiable risk factors, it was big news in the brain health world. The three new factors have been studied for decades for their impact on long term brain health. Now, according to the Commission, there’s enough solid evidence to add them to their list: traumatic brain injury, excessive alcohol consumption, and air pollution.
The Lancet Commission defines excessive alcohol consumption as more than 21 units of alcohol per week. Units of alcohol, a standard for measuring alcohol content in the U.K., should not be confused with the number of drinks. Many common drinks account for up to three units each. An eight-ounce glass of wine, for example, has about three units of alcohol.
Take-Away for Brain Health: There are now twelve modifiable risk factors for dementia as recognized by this conservative body of experts. Here’s what they mean for you:
- Wear a helmet whenever your brain is at risk for trauma
- If at all possible, minimize your exposure to air pollution
- Limit alcohol intake to less than 21 units per week—for instance, under 7 standard drinks per week
- Stay physically active throughout life—shoot for 150 minutes of aerobic exercise per week
- Correct hearing loss with hearing aids if impaired
- Maintain a healthy weight throughout life—defined as a body mass index between 18 and 25
- Treat or reverse diabetes with lifestyle measures and medical intervention
- Treat blood pressure aggressively at mid-life, keeping the systolic (top) number under 130 mm Hg
- Avoid all tobacco products
- Encourage social and cognitive engagement, especially later in life, to combat depression, loneliness, and social isolation
- Prioritize childhood education for all, worldwide
More Evidence That Eating Fish Protects the Brain
A diet rich in seafood mitigates the detrimental effects of air pollution on the brain
Numerous studies have documented a strong association between consuming fish and seafood and a reduced risk of developing Alzheimer’s disease. In fact, a landmark study in the journal JAMA Neurology4 showed that eating just one fish or seafood meal a week can reduce your risk by 40 to 60%. Now researchers postulate that the long chain fatty acids in fish can protect the brain from the impact of air pollution—an important factor in brain health.
In an elegant study published in the journal Neurology5 in August 2020, researchers evaluated a group of 1,315 women at risk for dementia because they lived in polluted areas. These women were between sixty-five and eighty, the ages in which air pollution seems to pose the greatest insult to the brain. The findings were remarkable. The women who ate one or two servings of fish or shellfish each week had greater brain volume when compared to those who rarely ate seafood. Brain volume is a marker for healthy brain aging. When brain volume is robust in the region of the brain called the hippocampus (where Alzheimer’s strikes first), it’s considered a positive factor against dementia.
Researchers postulate that eating one or two servings of fish or shellfish each week provided these women with enough omega-3 long chain fatty acids, in particular, DHA (docosahexaenoic acid), to mitigate the detrimental impact of pollution on the brain. The caveat: women who ate mostly fried seafood did not exhibit the beneficial effect.
Take-Away for Brain Health: Living in an air polluted environment can’t always be avoided. Women at risk may combat the detrimental effects of pollution on the brain by boosting intake of omega-3-rich fish or shellfish once or twice a week. Using brain-friendly cooking methods, like slow-roasting, braising, and grilling over indirect heat, are preferable to frying to protect the seafood’s beneficial fatty acids.
- Morris, M. C., Tangney, C. C., Wang, Y., Sacks, F. M., Bennett, D. A., and Aggarwal, N. T., MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s Dement., 2015, 11, 1007–1014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4532650/
- Holland, T. M., Agarwal, P., Wang, Y., et al., Dietary flavonols and risk of Alzheimer dementia. Neurology, 2020, 94, e1749–e1756. https://n.neurology.org/content/94/16/e1749
- Livingston, G., Huntley, J., Sommerlad, A., et al., Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet, 2020, 396, 413–446. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30367-6/fulltext
- Morris, M. C., Evans, D. A., Bienias, J. L., et al., Consumption of fish and n-3 fatty acids and risk of incident Alzheimer disease. Arch. Neurol., 2003, 60, 940–946. https://jamanetwork.com/journals/jamaneurology/fullarticle/784412
- Chen, C., Xun, P., Kaufman, J. D., et al., Erythrocyte omega-3 index, ambient fine particle exposure, and brain aging. Neurology, 2020, 95, e995 LP-e1007. https://n.neurology.org/content/early/2020/07/15/WNL.0000000000010074