One food found in most people’s kitchens is being linked with lower cholesterol after some 30 years of studies.
Cholesterol is a type of fat found in your blood and you need a certain amount of cholesterol for all your body cells and to produce important hormones.
However, according to the Irish Heart Foundation, if there is too much cholesterol in your blood, it sticks to your artery walls to form atheroma or plaque.
Having high cholesterol is one of the risk factors which increase your chances of getting heart disease and stroke.
Managing cholesterol often requires a combination of a good diet, regular exercise and medication and one food that has been positively linked with good cholesterol is garlic, as the Express reports.
Researchers have speculated that the food could help cholesterol and 30 years of study have suggested it is maybe slightly better than a literal placebo.
A 1993 meta-analysis of available research found a positive association between garlic and lower cholesterol.
The authors said: “The best available evidence suggests that garlic, in an amount approximating one half to one clove per day, decreased total serum cholesterol levels by about 9% in the groups of patients studied.”
This study looked only at people with total cholesterol levels greater than 200mg/dL.
Later research has disputed the extent to which garlic does actually reduce cholesterol levels.
A study from 2000 examined exclusively randomised, double blind placebo trials.
This means that both the researchers and patients did not know who was receiving the garlic supplements and who was receiving a placebo treatment.
The researchers looked at the role of garlic as supplements rather than the use of garlic in cooking.
Among people who had cholesterol levels above 200mg/dL, they saw a decrease of roughly 15.7mg/dL.
The researchers concluded their study by saying: “The available data suggest that garlic is superior to placebo in reducing total cholesterol levels.
“However, the size of the effect is modest, and the robustness of the effect is debatable.
“The use of garlic for hypercholesterolemia is therefore of questionable value.”
The analysis also looked at dietary trials for garlic.
These studies failed to find a significant difference between garlic and the placebo, with the average change in cholesterol being 4.3mg/dL.
These types of medicinal studies need to work hard to ensure that external factors like the placebo effect do not contaminate their results.
There are also risks when reading the scientific literature such as publication bias.
A study that fails to find any correlation between garlic and cholesterol is less likely to be published.
This means that when large reviews collect the available data from all published studies, they might be collecting a biased sample by looking at only the studies that made it to publication.