Large study from Canada
Researchers from Canada's University of Toronto and St Michael's Hospital have found that people who ate diets rich in plant-based foods known for lowering LDL-cholesterol, including plant sterols, soy foods, nuts and plant-based fibers showed reductions in LDL-cholesterol by 13% after six months. The average reduction in LDL-cholesterol went from 171 mg/dL on average down 25 mg/dL to 156 mg/dL of LCL-c.The study was published in this month's issue of the Journal of the American Medical Association.
The study followed 345 volunteers who were either instructed to eat a low-saturated fat diet or were given specific dietary advice to eat certain foods known to lower cholesterol during clinic visits. Their LDL-cholesterol levels Those who ate the low-saturated fat diet showed a 3% reduction in LDL-cholesterol levels during the same period. Their levels reduced from the average of 171 mg/dL to 168 mg/dL.
The researchers also divided the specific-foods diet into two additional groups, one that was given two sessions of advice during the six months and the other, given seven clinical dietary sessions during the six months. These two groups showed little difference in their resulting LDL-cholesterol levels. The group given seven advice sessions had 13.8% average reduction in LDL-cholesterol, while the group given two advice sessions showed an average of 13.1% reduction in LDL-cholesterol.
This latter result indicates that most people will adhere to diet advice when given occasionally as compared to frequently.
The overall result, however, is consistent with the multitude of research that has shown that plant sterols, cultured soy foods, nuts and high fiber foods specifically reduce LDL-cholesterol.
LDL-cholesterol and heart disease
Higher LDL-cholesterol levels have been associated with higher incidence of heart disease, atherosclerosis (hardening of the arteries), strokes and other cardiovascular issues. This is because LDL-cholesterol is less stable, and readily oxidizes. This oxidation produces free radicals that damage the walls of the blood vessels. This causes scaring, which tends to harden the arteries, as well as releases scar tissue into the blood. This release is what causes thrombosis.Plant sterols, also called phytosterols, are compounds found in most plant foods, including fruits, vegetables, seeds and nuts. There are a variety of different types of sterols, including avenasterol, campesterol and beta sitosterol. These are the lipids that make up the cells membranes of plants. A healthy plant cell membrane made of these phytosterols helps protect the plant's cells from becoming vulnerable to free radicals.
They also help reduce oxidized radicals in human nutrition because they attach and neutralize unstable lipids within the intestines.
What foods are highest in sterols?
Foods high in sterols include fresh corn, with 952 milligrams per 100 grams, rice bran, with 1055 milligrams per 100 grams, wheat germ with 553 milligrams per 100 grams, and flax seed with 338 milligrams per 100 grams. Nuts also have good sterol content. Cashews have 146 milligrams per 100 grams and peanuts have 206 milligrams per 100 grams.The Canadian researchers concluded:
"Use of a dietary portfolio compared with the low-saturated fat dietary advice resulted in greater LDL-C lowering during 6 months of follow-up."
The "dietary portfolio" was the specific foods mentioned, offered within nutrition counseling sessions that taught the volunteers how to incorporate these LDL-cholesterol-lowering foods into their diets.
REFERENCES:
Jenkins DJ, Jones PJ, Lamarche B, Kendall CW, Faulkner D, Cermakova L, Gigleux I, Ramprasath V, de Souza R, Ireland C, Patel D, Srichaikul K, Abdulnour S, Bashyam B, Collier C, Hoshizaki S, Josse RG, Leiter LA, Connelly PW, Frohlich J. Effect of a dietary portfolio of cholesterol-lowering foods given at 2 levels of intensity of dietary advice on serum lipids in hyperlipidemia: a randomized controlled trial. JAMA. 2011 Aug 24;306(8):831-9.