Diet and Health FAQ

Tagged As: low cholesterol diet example

Question:
LOW-FAT diets can lead to depression, according to doctors who have found a link between anxiety and low cholesterol levels in women. An investigation of 121 healthy young females found that those with low cholesterol were more likely to score high on measures of depression and anxiety than women with normal or high cholesterol. Some fat-reducing diets can cut cholesterol levels by around 10 per cent, and so possibly trigger anxiety or depression in women with already naturally low levels. While we certainly don't advocate that women indulge in high-fat foods, our data do suggest that women with naturally low cholesterol could benefit from raising their cholesterol through healthy dietary measures, like consuming more fish or fish oil, said Prof Suarez of Duke University, North Carolina. A previous study of elderly men has also suggested the link, while another has related low cholesterol levels to violent death and suicide, mostly in men. Now there is a compelling body of evidence in both men and women that low cholesterol is a potential predictor for depression and anxiety in certain individuals, said Prof Suarez, whose study will be published next month in the journal Psychosomatic Medicine. The study of low density lipoprotein concentrations in the blood indicates that relatives and doctors should monitor the mental state of patients on drugs to cut cholesterol levels. Someday, screening for depression may encompass a cholesterol test, especially at significant points in a woman's lifetime when her cholesterol levels are known to drop, said Prof Suarez. After childbirth, for example, a woman's cholesterol level drops precipitously, giving rise to the theory that some cases of post-natal depression result from low cholesterol. Prof Suarez said there was evidence to suggest that having low cholesterol altered the way brain cells functioned. It was believed that brain cells with low levels of cholesterol had fewer receptors for the mood-stabilising chemical serotonin.

Answer:
Don't worry, a low-fat or low cholesterol diet has not been linked to depression. In one study, one sub-population showed a weak correlation between very low cholesterol levels (similar to those reportedly achieved by posters here on both low carb and low fat/cholesterol diets), not diets, and depression. Most researchers feel that some forms of depression (or their true causes) seem to lead to low cholesterol levels, not the other way around. The report of the study below is a typical example of bad scientific understanding. In this case, assuming that a weak correlation found in one study sample between elements A (low cholesterol blood levels) and B (depression) implies causation between another element C (low cholesterol diets) and B. An aside on another topic: Typical bibliographies of bad nutrition advocacy often include hundreds of such erroneous writings, which is why a mere bibliography of studies should never impress you, coming from anyone (not even someone you agree with). In fact, a very long bibliography with no detailed discussion of the design (not just the result, but the design) of each and every study is usually a tipoff to bad science. Another tipoff is anyone asserting causation has been proved in human nutrition. The type of study that would be needed to prove causation is not ethical and so is not done. The studies that can get closest to it are huge studies of thousands of people over decades and these studies probably number under 10. There isn't enough funding to do many of these types of studies. Also, when discussing the results, the study should be quoted verbatum on the topic, since typically, a lay person with a particular axe to grind overstates the conclusions that the authors of the study reached and omits the caveats and cautions that all good researchers include in their conclusions and which will be found in the actual text of the study.