Cardiovascular disease cholesterol effects

N. de Rons, Trans fatty acids, HDL-cholesterol, and cardiovascular disease risk Effects of dietary changes on vascular reactivity, Wageningen Universiteit, Wageningen, the Netherlands, 2001. 

Numerous researchers have drawn attention to the beneficial properties that avocado could provide to human health. Some of these healthy benehts have been summarized in Figure 8.1. Wilson Grant, in 1960, published the hrst clinical study where avocado intake was associated with the maintenance of normal serum cholesterol levels, or even with their reduction [7]. Later on, in the 90s and beginning of 2000 there was an increase in the number of works that studied the relationship between avocado fat and its effect on cardiovascular diseases, cholesterol, lipid profile, weight control, and diabetes [8-16]. While the principal healthy benehts attributed to avocado fruit are the aforementioned, some others have also been evaluated, such as prevention and treatment of osteoarthritis [17,18], anticancer properties [19-24], protective activity against liver injury [25], skin protection [26-28], reduction of risk of macular degeneration [29], inhuence on short-term memory [30], antioxidant activity [31-37], reduction of metabolic syndrome risk [38,39], and anti-inhammatory effects [31,32,40]. 

Dietary fibre is a beneficial material for constipation, gastric and duodenal ulcers, haemorrhoids, rectum and colon (colorectal) cancer, commonly known as bowel cancer, and other diseases. Eating foods high in fibre is recommended for the modulation of glucose levels in blood serum and in some forms of diabetes (especially type 2 diabetes). This also has the effect of reducing serum cholesterol level, and can thus help to prevent cardiovascular diseases. The effect is explained by the reduced absorption of cholesterol from viscous foods and by cholesterol binding to fibre. 

Unfortunately, excess consumption of fatty foods has been correlated with serious human disease conditions. Effects on cardiovascular disease (95), cancer (96), and function of the immune system (97) have been shown. Numerous studies have been conducted to determine the effects of saturated, monounsaturated, and polyunsaturated fatty acids on semm cholesterol and more recently high density Hpoprotein (HDL) and low density Hpoprotein... 

Thus, it is apparent that soya, some soya products and linseed oil influence blood lipid levels, particularly cholesterol and LDL cholesterol. While the extent of the reduction appears to largely depend on an individual s initial serum cholesterol level, the maximum reductions observed are of the order of 10-15%. For hyperlipidemic individuals this may not be a marked reduction, but such an effect on the general population may well have a beneficial effect on the overall incidence of cardiovascular disease and atherosclerosis. The possibility that non-phytoestrogenic dietary components may contribute to the hypocholes-terolemic properties cannot, however, be discounted. Indeed, certain types of dietary fibre have been shown to have a hypolipidemic effect via their ability to increase faecal excretion rates. 

Observational studies have suggested possible favourable effects of estrogen replacement therapy (ERT) on the risk of coronary heart disease in postmenopausal women. Since elevated plasma cholesterol has been identified as the primary risk factor for cardiovascular disease, investigations have focused on the inverse association between plasma cholesterol concentration and soy protein consumption. The cholesterol-lowering properties of soy have been demonstrated, and a good correlation has been found in... 

Cardiovascular disease (CVD) is characterized by the involvement of the heart and allied vascular system. High cholesterol, associated lipid abnormahties and high blood pressure are recognized as the major risk factors of CVD. There have been several animal experiments and clinical studies using rice bran and rice bran oil, which have demonstrated a hypocholesterolemic effect (Raghuram et al., 1989 Rukmini and Raghuram, 1991 Sugano and Tsuji, 1997). The mechanisms involved are briefly summarized. 

In addition to effects on bone, raloxifene may have effects in breast tissue and on the cardiovascular system. A secondary end point of the MORE trial evaluated the effects of raloxifene on the primary prevention of breast cancer and found a significant reduction in all types of breast cancer.33 Raloxifene decreases total and low-density lipoprotein (LDL) cholesterol,34 and studies are evaluating its effect on reducing the risk of cardiovascular disease.35... 

For people who are at risk of cardiovascular disease due to high plasma LDL cholesterol levels, lifestyle changes to control plasma cholesterol levels are the first and best place to start. When efforts to control plasma cholesterol levels by diet and exercise fail, people frequently turn to drugs, some of which are effective in producing substantial lowering of cholesterol levels and realizing associated clinical benefits. 

At menopause, the production of estrogens in females is markedly reduced. This leads to a number of unpleasant effects, including hot flashes and night sweats. More important for long-term health, the estrogen decrease is associated with an increased risk of cardiovascular disease and osteoporosis. The action of estrogens decreases plasma cholesterol and helps maintain good bone mineral density. 

Whole grains, beans, vegetables all containing high content of fibre Cardiovascular disease, cancer Fibre has two effects (i) lowered cholesterol levels (ii) increased production of volatile fatty acids by microorganisms in colon... 

The hypothesis that dairy foods contain a cholesterol-lowering milk factor evolved from the observation that Maasai tribesmen of East Africa have low serum concentrations of cholesterol and a low incidence of cardiovascular disease in spite of their consumption of 4 to 5 liters/day of fermented whole milk (Mann and Spoerry 1974). Subsequently, sufficient amounts of yogurt, as well as unfermented milk (whole, lowfat, skim), were reported to exhibit a hypocholesterolemic effect both in humans and in laboratory animals in several studies (Mann 1977 Howard and Marks 1977, 1979 Nair and Mann 1977 Kritchevsky et al 1979 Richardson 1978 Hussi etal. 1981). However, not all investigators have observed a hypocholesterolemic effect of milk. This inconsistency may be explained in part by differences in the experimental design and in the specific type of dairy food used by investigators. 

Although elevated levels of cholesterol and LDL in human plasma are linked to an increased incidence of cardiovascular disease, recent data have shown that an increase in concentration of HDL in plasma is correlated with a lowered risk of coronary artery disease. Why does an elevated HDL level in plasma appear to protect against cardiovascular disease, whereas an elevated LDL level seems to cause this disease The answer to this question is not known. An explanation currently favored is that HDL functions in the removal of cholesterol from nonhepatic tissues and the return of cholesterol to the liver, where it is metabolized and secreted. The net effect would be a decrease in the amount of plasma cholesterol available for deposit in arteries (see... 

Lipid changes seen with the most widely used combined oral contraceptives comprise an increase in low density lipoprotein and reductions in high density lipoprotein and cholesterol. The third-generation products have these effects to a much smaller extent, leading to claims that they would be less likely to have long-term adverse cardiovascular effects related to atherosclerosis. However, such a claim reflects an all too readily adopted belief that the lipid changes produced by the more traditional combined oral contraceptives are in this respect capable of causing this type of (primarily arterial) cardiovascular disease. This is of itself far from certain. 

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