Elevated blood pressure (BP) is the primary risk factor for loss of brain function in older Americans. Increased BP is the #1 risk factor for not only stroke but also more insidious damage to the smallest arteries delivering blood to the brain's white and grey matter that control higher brain functions. In large part the damage to the arterioles is done by an electrolyte imbalance that constricts these blood vessels to the point where inadequate blood reaches the brain's white and grey matter. Excessive salty intake, especially when accompanied by inadequate potassium leads to excessively constricted blood vessels throughout the body. Areas of the body that are metabolically very active such as the brain, kidneys, and retina tend to suffer the most in those with elevated BP. Not surprisingly elevated BP in mid-life is strongly associated with an elevated risk of dementia over time.

A recent study of 1424 participants in the Women's Health Initiative Memory Study examined the impact of BP and its treatment on cognitive function and the loss of white matter in the brain. These older (>64y) women underwent MRIs which demonstrated that higher BP was strongly associated with the loss of white matter in their brains. The authors conclude that ".. it is clear that even moderately elevated BP is associated with silent vascular disease in the brain that contributes to dementia."[i]Aside from reducing dietary salt and increasing potassium to lower BP and increase blood flow to the brain there are two other dietary factors likely to reduce the constriction of arterioles seen in most older Americans and protect against both stroke and dementia. Dr. Kim-Shapiro at Wake Forrest University recently demonstrated that drinking beet juice (a rich source of nitrates) increased blood flow within the brain's white matter in older adults. The improvement in blood flow was greatest in the deep white matter areas of the frontal lobe where lesions are most associated with the development of dementia.[ii] Foods rich in nitrate includes beets, celery, lettuce, parsley, broccoli, carrots, radishes, rhubarb, spinach, melons and turnip greens. Eating more foods rich in anthocyanins such as blueberries, black beans, blue corn, and purple potatoes also help dilate small blood vessels and protect against stroke and other cardiovascular ills.[iii]Bottom Line: Dramatically reducing intake of salty processed foods and eating more whole fruits and vegetables would certainly significantly reduce the risk of CVD and improve blood flow to the brain in older Americans and likely dramatically cut the risk dementia as well. By James J. Kenney, PhD, RD, FACN[i] Kuller JH, et al. Relationship of hypertension, blood pressure, and blood pressure control with white matter abnormalities in the WHIMS - MRI Trial. J Clin Hypertens 2010;12:203-12[ii] doi:10.1016/j.niox.2010.10. 2010[iii] Wallace TC. Anthocyanins in Cardiovascular Disease. Adv. Nutr. 2011;2:17