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You have always been told a diet rich in saturated fatty acids is risk for your cardiovascular health, haven’t you? Well, a study published in the American Journal of Clinical Nutrition claims there is no direct link between intake levels of saturated fatty acids and the risk for cardiovascular disease. Nonetheless, it is definitely important to pay attention the the quality of fats we eat.
The (good?) news comes from a team of researchers from the Children’s Hospital Oakland Research Institute in Oakland, Cal., and the Departments of Nutrition and Epidemiology at Harvard School of Public Health in Boston, Mass., who performed a meta-analysis on prospective epidemiologic studies. A somewhat complicated way to say that a group of initially healthy people – called ‘a cohort’ – is followed over time to investigate if occurrence of disease is related to the exposure of dietary and other lifestyle factors. In this case, this cohort were monitored to determine if a diet rich in saturated fatty acids has any influence on the risk of coronary heart disease, stroke, and cardiovascular disease.
Results are then compared to those from a number of different studies collected and these are then jointly analysed in order to reach a general conclusion based on the accumulated scientific findings in the field.
Over all some twenty-one studies matched the inclusion criteria for the current meta-analysis. Together these comprised 347,747 individuals of which some 11,000 developed any cardiovascular disease.
The results of the analysis showed no significant association between high intake of saturated fatty acids and an increased risk of coronary heart disease, stroke or cardiovascular disease. Age, sex, and study quality were factors taken into account in the analysis, but they did not impact on the outcome.
The results from this meta-analysis are in line with the existing knowledge that only reducing the intake of saturated fatty acids is not likely to have any beneficial effect on the risk for cardiovascular disease.
Previous studies however suggest that a reduction in cardiovascular disease risk may be obtained by replacing a major part of the dietary saturated fatty acids with polyunsaturated fatty acids. This very opinion is shared by the World Health Organization (WHO) and the Food and Agriculture Organization (FAO), which in a recent consultation paper on fats and health concluded that there is convincing evidence of decreased coronary heart disease risk when saturated fatty acids are replaced with polyunsaturated fatty acids.
Both findings from previous epidemiological studies and clinical trials support that substituting saturated fatty acids with polyunsaturated fatty acids is more beneficial for cardiovascular disease risk than replacing the saturated fatty acids with carbohydrates (that is, the so-called Mediterranean diet). In the current meta-analysis no conclusions could be drawn on the effects on cardiovascular disease risk of replacing saturated fatty acids with either polyunsaturated fatty acids or carbohydrates, since among the studies included in the analysis only a few addressed this hypothesis. More data are needed to determine whether cardiovascular disease risks are likely to be influenced by the specific nutrients used to replace saturated fatty acids.
Fat is an essential component of our diet; we all need to eat certain amounts to stay in good health. But, it is not only the total amount of fat that is important, we also need to think about what kind of fats we choose to eat. In general, we should eat more of the ‘good’ unsaturated fats, including essential omega-3 and omega-6 polyunsaturated fatty acids and monounsaturated fatty acids and less of the ‘bad fats’, such as certain saturated fatty acids. Studies have shown that a high consumption of saturated fatty acids, more precisely lauric, myristic and palmitic acid, may increase the levels of ‘bad’ LDL-cholesterol in the blood. Elevated blood levels of LDL-cholesterol is a known risk factor for cardiovascular disease and replacing saturated fatty acids with polyunsaturated fatty acids in the diet has been shown to be an effective way to reduce these.
The recommendation to persons who wish to reduce their risk of cardiovascular disease is to replace the saturated fatty acids in their diet with polyunsaturated fatty acids. It is considered that a diet with around 30% of daily energy coming from fat is consistent with good health. A maximum of 10-11% of our daily calories should originate from saturated fatty acids.