What role do folate and vitamins B6 and B12 play in relation to heart disease?
Recently it was determined that higher levels of homocysteine in the blood can increase heart disease risk possibly by negatively influencing blood clotting and vasodilation. Homocysteine is naturally produced in the cells as they go about their molecule-making business. As displayed in Folate Recycling Figure, homocysteine can be converted to the amino acid methionine via the assistance of folate and vitamins B6 and B12. Thus having adequate levels of these vitamins can help manage the level of homocysteine. Over the next few years ongoing research should shed more light on the exact role homocysteine plays in heart disease development and the best way to apply folate and vitamin B6 and B12.
Can fiber impact heart disease prevention?
Dietary fiber, especially soluble fiber found in oats, barley and legumes (e.g. beans, peas and lentils) and psyllium can have a positive impact on blood cholesterol levels. The relationship between fiber (namely beta-glucans) from these food sources and cholesterol lowering has lead to the development of health claims that food manufacturers can use on packaging like the one below.
In order for claim to be used a food product one serving must contain either 0.75 g of oat or barley fiber or 1.7 g psyllium fiber.
“Soluble fiber” from foods such as (name of soluble fiber source or product), as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. A serving of [name of food product] supplies X grams of the [necessary daily dietary intake for the benefit] soluble fiber from [name of soluble fiber source] necessary per day to have this effect."
Soluble fibers from these sources influence blood cholesterol levels by interacting with cholesterol digestive tract and decreasing its absorption. These fibers may also undergo breakdown by bacteria in the colon and the bi-products have been notes to potentially reduce cholesterol production in the liver.
How can plant sterols help lower heart disease risk?
Plants make sterol molecules that are very similar to cholesterol human and other animals produce. In fact, many of us might have a hard time telling the difference between these plant sterols and animal cholesterol (see Phytosterol Figure). Research by scientists in the United States and around the globe (such as in Finland) has suggested that sterols such as sitosterol, stigmasterol, campesterol, and sitostanol can lower blood cholesterol levels.
Phytosterols appear to block the absorption of cholesterol in the digestive tract which in turn lowers the level of total and LDL cholesterol in the blood. As these sterols are found in plant oils (especially unrefined oils), this may help explain some of the cholesterol-reducing properties of those oils. Phytosterols are also found in nuts, seeds, whole grains and legumes. Commerically available spreads such as Take Control® and Benecol® are produced with phytosterols to be used by people trying to lower their cholesterol.
Can eating more flavonoids lower the risk of heart disease?
In short, probably. However, the details and recommendations are still a little out of reach at this point. Flavonoids (isoflavones or isoflavonoids, flavones, flavonols, catechins, and anthocyanins) are a class of chemicals produced by plants and are often called polyphenolic compounds with respect to their molecular structure. Onions, citrus, some teas, and red grapes (red wine) contain a flavonoid called quercetin which is a potent antioxidant and seems to favorably impact blood pressure.
Researchers in the United States, Finland, and around the world have determined that people who eat or drink less of flavonoids have a higher death rate from heart disease. Some of these flavonoids may act to decrease the level of total and LDL-cholesterol in the blood, while others may decrease free-radical activities, thereby protecting LDL from oxidation as well as helping to protect the walls of the arteries. So again, eat more fruits, vegetables, and whole grains and, if you like, enjoy a glass or two of red wine daily or a few times a week.