Athlerosclerosis and Alzheimer?s Disease

Alzheimer’s disease (AD) appears to share most of the same risk factors associated with an increased risk of atherosclerosis and coronary artery disease (CAD). These include higher LDL-C level, obesity, type 2 diabetes, hyper- tension, smoking, inactivity, and elevated serum homocysteine level. Moderate alcohol intake has long been known to cut the risk of CAD events and recent large meta-analysis of 143 stud- ies published in the August 2011 Neuropsychiatric Disease and Treatment journal found moderate social drinking reduced the risk of AD and dementia by 23%. Just as atherosclerosis is known to begin many years before patients develop symptomatic CAD (angina or heart attacks) the beta-amyloid plaques that develop between brain cells and are believed to contribute the loss of brain func- tion and are believed to start forming many years before AD can be diagnosed with current tests. The Whitehall II study in England started following over 10,000 civil servants when they were around age 40 largely in order to establish risk factors for coronary artery disease. Nearly 20 years later Dr. Singh-Manox undertook six cognitive function tests on over 5000 of these participants. She found both men and women who developed CAD in their 40s and 50s were significantly more likely to show a greater loss of several measures of cognitive function. The earlier in life they were diagnosed with CAD the greater the likelihood that they would show impairment of cognitive function.1 A study published in the September 2011 issue of Neurology examined the brains of people whose cholesterol levels were checked many years earlier found people with higher LDL-C levels (>155mg/dl) had an increased the likelihood of having more beta-amyloid plaques in their brains at death compared to those who had LDL-cholesterol levels <106mg/dl. Even after cor- recting for other CAD risk factors associated with developing AD such as age, sex, body weight, activity level, blood pressure, and insulin resistance those with the higher LDL-C levels were still 8 times more likely to display pathological brain changes as- sociated with AD than those with lowest LDL-C levels.Elevated levels of homocysteine (Hcy) in the blood have been as- sociated with an increased risk of both CAD and AD. Low levels of several B-vitamins can contribute to elevated levels of Hcy leading to hopes that supplements of these B-vitamins might reduce the risk heart disease and senility. Dr. David Smith at Oxford University and colleagues examined the impact taking either a placebo or a B-vitamin supplement (folic acid 800mcg; pyridoxine 20mg; and vitamin B-12 500mcg per day) in a group of 266 older subjects with mild cognitive impairment. Cognitive function and brain atrophy were assessed before and after two years and data showed the rate of brain atrophy in the B-vitamin group was slowed by about 30% compared to the placebo group. In subjects, whose initial Hcy level were in the top 25% (>13mg/dl) the slow- down in brain atrophy was even more dramatic (53% less than the controls). The authors of this trial conclude: “The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B-vitamins.”2 An increased omega-3 fatty acid intake appears to reduce the risk of both CAD and AD. A recent meta-analysis found that omega-3 fatty acids supplements lowered serum Hcy levels by 25%. 3A 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 (>64) 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.”4 More recently a study of 1262 healthy older people in Canada were divided into 3 groups based on their sodium intake. They found those with the highest sodium in- take were more significantly more likely to lose cognitive function over the next 3 years than those with lowest sodium intake.5Bottom Line: A diet lower in salt, refined carbohydrates, fatty meats and dairy products and higher in minimally processed plant foods and omega-3 seafoods helps prevent CAD and many other ills linked modern Western diet and lifestyle. The evidence continues to mount that AD shares most of the same risk factors as CAD. People who adopt a heart healthy diet may get a bonus of a reduced risk of dementia as well.By James J. Kenney, PhD, FACN1. Eur Heart J 2008;29:2100-72. Smith AD, et al. PLoS ONE5(9):e12244.doi:101371/ journal.pone.00122443. Huang T, et al. doi:10-.1016/j. nut.2010.12.0114. J ClinHypertens 2010;12:203-125. Fiocco AJ, et al. doi: 10.10016/j. neurobiolaging.2011.07.004