It has been more than proven that our diet directly influences the risk of developing diseases such as obesity or diabetes, but there is increasing evidence that brain health can also be affected by poor dietary choices or by the lack of certain essential nutrients. . New research has now revealed that in people with Alzheimer’s disease brain levels of dietary lutein, zeaxanthin, lycopene and vitamin E are half that of healthy brains. Higher dietary levels of lutein and zeaxanthin have been linked to better cognitive functions and a lower risk of dementia or Alzheimer’s disease.
The research has been conducted by scientists at the Virginia Tech College of Carilion School of Medicine. “This study, for the first time, demonstrates deficiencies in important dietary antioxidants in Alzheimer’s brains. These results are consistent with large population studies that found that the risk of Alzheimer’s disease was significantly lower in those who ate diets rich in carotenoids, or they had high levels of lutein and zeaxanthin in their blood, or they accumulated in the retina as macular pigment,” said C. Kathleen Dorey, a professor in the Department of Basic Science Education at the medical school. “Not only that, but we believe that eating diets rich in carotenoids will help keep the brain in optimal condition at all ages.”
Because normal brain functions and the response to misfolded proteins constantly generate reactive oxidant molecules, the brain is vulnerable to cumulative oxidative damage, which can be prevented by antioxidants in a healthy diet. Carotenoids are powerful antioxidants that are typically found in colorful plants. Lutein is especially abundant in kale and spinach, and zeaxanthin is most abundant in corn and orange bell peppers.
“The risk of Alzheimer’s disease was significantly lower in those who ate diets rich in carotenoids, or had high levels of lutein and zeaxanthin in their blood.”
Dorey and Neal E. Craft, of Craft Technologies in Wilson, North Carolina, first reported in 2004 that the brain selectively accumulated carotenoids, such as lutein, zeaxanthin, and beta-cryptoxanthin. Since then, researchers around the world have shown that individuals with higher levels of lutein and zeaxanthin in their macular pigment enjoy better cognition and that those with higher levels of lutein and zeaxanthin in their diet or accumulated in their macular pigment have less risk of dementia.
The Memory and Aging Project at Rush University followed the diet and cognitive performance of more than 1,000 participants living in Chicago for more than a decade, evaluating their carotenoid intake, and found that those who followed the MIND diet — which combines characteristics of the Mediterranean diet and the DASH diet for high blood pressure—and ate more antioxidant-rich fruits, nuts, vegetables, and fish, and lower levels of meat and sweets, reduced their risk of being diagnosed with Alzheimer’s, and had a higher cognitive performance before death and less brain pathology related to Alzheimer’s disease. In addition, those with the highest intake of total carotenoids or lutein/zeaxanthin over a decade had a 50% lower risk of developing Alzheimer’s.
Dietary antioxidant deficiency in Alzheimer’s brains
In a study of carotenoids in brains with and without Alzheimer’s disease brain pathology, Dorey-Craft’s team showed that brains with Alzheimer’s neuropathology had significantly lower levels of lutein, zeaxanthin and lycopene, and tocopherols. Lycopene, zeaxanthin, and retinol concentrations were half those found in age-matched brains without Alzheimer’s disease pathology.
This new evidence of selective carotenoid and tocopherol deficiencies in the brains of subjects with Alzheimer’s disease further supports growing evidence that increased dietary carotenoid intake may delay cognitive decline before and possibly after diagnosis with the disease. Alzheimer’s.
Research has also shown that the retina selectively accumulates lutein and zeaxanthin from the diet, forming a visible yellow macular pigment that improves vision and protects photoreceptors. By noninvasively measuring the optical density of patients’ macular pigment, researchers can estimate the concentration of lutein and zeaxanthin in the brain. The results have been published in Journal of Alzheimer’s Disease.
“Recent advances in new therapies for Alzheimer’s disease hold promise as an effective way to slow disease progression,” Dorey said. “I would love our data to motivate people to keep their brains in peak condition with a colorful diet rich in carotenoids and regular exercise. Available studies suggest this may also reduce the risk of dementia.”
