Nutrition and Risk of Stroke

Abstract

Nutrition is far more important in stroke risk than most physcians suppose. Healthy lifestyle choices reduce the risk of stroke by ~80%, and of the factors that increase the risk of stroke, the worst is diet: only ~0.1% of Americans consume a healthy diet, and only 8.3% consume a somewhat healthy diet. The situation is probably not much better in most other countries. A Cretan Mediterranean diet, high in olive oil, whole grains, fruits, vegetables and legumes, and low in cholesterol and saturated fat, can reduce stroke by 40% or more in high-risk patients. The role of the intestinal microbiome in cardiovascular risk is emerging; high levels of toxic metabolites produced by intestinal bacteria from meat (particularly red meat) and egg yolk are renally excreted. Patients with renal impairment, including the elderly, should limit red meat and avoid egg yolk, as should other patients at high risk of stroke. Salt intake should be limited to 2⁻3 grams per day. Metabolic B12 deficiency is common and usually missed. It has serious neurological consequences, including an increase in the risk of stroke. It now clear that B vitamins to lower homocysteine reduce the risk of stroke, but we should probably be using methylcobalamin instead of cyanocobalamin.

Keywords: B vitamins; Mediterranean diet; dietary cholesterol; eggs; homocysteine; nutrition; sodium; stroke.

Figure 1

Diet is the worst of the risk issues in the USA. Prevalence (unadjusted) estimates for poor, intermediate and ideal cardiovascular health for each of the seven metrics of cardiovascular health in the American Heart Association 2020 goals, US children aged 12–19 years, National Health and Nutrition Examination Survey (NHANES) 2011–2012. * Healthy diet score data reflect 2009–2010 NHANES data. (Reproduced by permission of Wolters Kluwer from: Mozaffarian D, Benjamin EJ, Go AS, Arnett DK, Blaha MJ, Cushman M, et al. Heart disease and stroke statistics—2015 update: A report from the American Heart Association. Circulation. 2015;131(4): e29–322.).

Figure 2

The Mediterranean diet. The Mediterranean diet is a high fat/low glycaemic diet with 40% of calories from fat; however, the fat is mainly beneficial oils such as olive and canola. Among men in the Seven Countries Study, the coronary risk in Crete was only 1/15th of that in Finland, where most of the fat was saturated fat (accompanied by cholesterol), and 40% of that in Japan, where the diet is a low-fat diet favouring fish. (Reproduced by permission of the artist, Cornelia Blik, from Willet and Stampfer [5]).

Figure 3

Polynomial and inverse regression, spline, loess fits for plasma tHcy with B 12. Solid, dotted, long dashed and short dashed lines represent loess, cubic polynomials, cubic polynomials of the inverse covariate and smooth splines, respectively. (Reproduced by permission of Karger from [44]).

Figure 4

Homocysteine metabolism. B12 = cobalamin. B6 = pyridoxine. MTH = methylenetetrahydrofolate. MTHFR = methylenetetrahydrofolate reductase. SAM = S-adenosylmethionine. SAH = S-adenosylhomocysteine. 5-Me THF = 5-methyl tetrahydrofolate.