You may have heard of the “Silver Tsunami” It’s the term used to describe the enormous number of people reaching 65 and older in the coming years. By 2050, the number of older Americans (primarily baby boomers) is projected to be 88.5 million. This is double its estimated population of 40.2 million in 2010 according to the United States Census Bureau. This aging population will have wide range implications involving our economy and health care system to name a few.
One of the major concerns is brain health…and one of the major risk factors in developing dementia is…living longer. It’s a catch 22 because even though living longer is thought of as a sign of health, it is an independent risk factor for cell changes, especially in the brain.
We now know that what you eat has a big impact on the brain. In fact…the right foods and combinations of foods can enhance memory, build new brain cells and help ward off Alzheimer’s disease. Many people will point to increasing antioxidant foods (primarily fruits and vegetables) as a way to mop up free radicals that can cause cell damage and enhance diseases such as cardiovascular disease, diabetes, cancer and dementia. But how do antioxidants work? And is there another mechanism by which beta-amyloid -the protein that accumulates excessively in the brains of Alzheimer’s patients- can be controlled?
What we have found is that plants have an elaborate method of protecting themselves by developing chemical defenses to ward off insects and other predators that want to eat them. These toxic chemicals that plants use against predators are consumed by us at low levels in fruits and vegetables. These substances actually cause a mild stress response that leads to resilience to cells in the body. This stress is the equivalent to exercise or going without food for a long period of time. But instead of the cells dying, they actually get stronger! This adaptation to stress and boosting cell resilience is called “hormesis”.
So you would think that the more of these fruits and vegetables you eat the better?! Well, that’s not true. Eating a small or moderate amount of a plant chemical has beneficial health effects. But when consuming too much, these toxic chemicals can cause harm. This may be why the bitter taste of many plants tells us not to eat too much or to simply avoid them. One example is Brazil nuts. Eating a few can help protect against cardiovascular disease and cancer, while consuming too much can poison the liver and lungs.
So too much of a good thing with supplements may not give us the effect we want. It may negate the health effects by impeding hormesis. This is because there are many ways that hormetic chemicals in plants act on the signaling pathways to enhance the functioning of neurons. Without getting too technical, some of the chemicals such as curcumin or the sulforaphane in broccoli can activate genes that encode antioxidant enzymes that eliminate free radicals. Chains of these biochemical events produce antioxidants or neurotrophic factors and eliminate damaged proteins which boosts stress resistance, regulates cellular energy more efficiently and most important, improves cognitive function! Timing of this stress response in a cell is critical to whether the cell benefits. Just as exercise (another hermetic effect) needs to be interspersed with periods of rest for growth and repair of cells, so does the consumption of plant chemicals. When eating fruits and vegetables, the body enters a stress resistance mode in which there is a reduction in making new proteins, and an increase in the removal of damaged molecules which can cause the cells to deteriorate. When the body rests and the stress is removed, protein synthesis increases and cells can repair. In the case of neurons, new connections among cells can occur during this recovery period which can stimulate the production of new neurons from stem cells deep in the brain called the hippocampus, connect with other neurons and increase learning and memory capacity. A good night’s sleep is enough rest and time for these cells to recover from exercise or exposure to plant chemicals consumed during the day.
Another key cellular defense involves the formation of a new family of proteins called sirtuins. One type in particular (SIRT1) can increase the life span of certain cells by calorie restriction. Resveratrol, found in red grapes and wine, activates SIRT1, which switches on multiple chemical pathways that induce hermetic effects.
So the take home:
Antioxidants are more complex in the way they work than we thought in protecting us from many diseases through hormesis. Get as many different antioxidants from whole foods because as you can see, they each have different brain boosting benefits:
1. Olive oil, green tea and leafy greens (spinach, kale and broccoli)- activate certain genes and reduce inflammation.
2. Beets, tomatoes and avocados- increase blood flow to the brain to promote neuron growth in the hippocamus (to help learning and memory).
3. Nuts (especially walnuts), curcumin and pomegranates- fight amyloid plaques that can accumulate and kill neurons.
4. Fish, blueberries, grapes, coffee and dark chocolate- increase the level of brain neurotrophic factor which supports the growth of new neurons.
Mild stress to the brain (especially exercise and even calorie restriction) is a good thing as long as we allow some recovery time.
Take care of your brain. It will thank you for years to come.
References: Mattson, M “What Doesn’t Kill You…” ScientificAmerican.com, July 2015. p.41-45.
Paturel, A. “Eat Your Way To Brain Health” . AARP Bulletin/Real Possibilities. October 2015. p. 12.
Photo by faith goble