Nutrition Meets Food Science

Is Cholesterol From Food Bad For Heart?

Dietary cholesterol has been most controversial nutrient in food. It became controversial after it was found that cholesterol in blood is responsible for causing numerous problems like cardiovascular disease, strokes and even gall stones. Cholesterol was first discovered in bile and gall stones in year 1769 by Poulletier and was named “cholesterine” by Chevreual in 1815. After this there were a series of discoveries by scientists who founded that cholesterol is actually carried in body by lipoproteins, as certain kinds of lipoproteins are implicated in various metabolic diseases. 

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Cholesterol is a wax like substance which is found in animals. Plants do not contain cholesterol, instead they have a substance called phytosterol. Cholesterol and fats cannot dissolve in blood as they are immiscible. Hence they are transported in body as packets which are covered with proteins called as lipoproteins (lipo- lipid and cholesterol proteins). Cholesterol and fats are important for normal functioning of body. Cholesterol in body is starting point of making many hormones and also vitamin D besides many other important functions. Its only when it becomes excess, especially a certain kind of lipoprotein, more specifically LDL that it is implicated

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About half a century ago, it was discovered that, that high levels of cholesterol were strongly linked to heart disease. Hence, all foods that contained cholesterol like eggs, organ meats naturally became the culprits. However, studies later showed that dietary cholesterol has a small impact on blood cholesterol. Synthesis of cholesterol is tightly regulated. If intake of cholesterol is high, endogenous cholesterol synthesis is down regulated thereby net cholesterol levels are maintained. In fact, saturated fats have a higher role in increasing cholesterol. There are certain individuals called the responders in whom, increased intake of dietary cholesterol increases their serum cholesterol level. These are very few. Most are non-responders where dietary cholesterol has a minimum impact on their serum cholesterol. In these individual’s dietary fat becomes more important.

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Although cholesterol is present in many foods, the most well know source of dietary cholesterol is egg. Due to this reason eggs have become most controversial foods. Each Egg has 200mg of cholesterol, but has moderate amount of saturated fats. Egg is the richest source of good quality protein besides carrying many vitamins. Hence it is a bag of good nutrition at cheap cost. Hence consuming an egg per day is not really an issue especially for non -responders.

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Does that mean, if we belong to non -responder category, we can consume as many eggs or as much organ meat as we like? the answer is NO. One has to understand, in nature food substances rarely occur in isolation. Most of the foods which are a rich source of cholesterol are also a rich source of saturated fat only exception being shrimps and shell fish. Saturated fats, especially high amounts, like those found in red meat, processed meat products like cold cuts, of these do increase serum cholesterol. Hence, it’s important to understand food matrix as a whole instead of concentrating on only one nutrient. Also, how this food is cooked, is important. In India, non vegetarian foods are cooked in lot of fat especially using saturated fat sources like ghee or coconut. That actually increases the saturated fat in meal further, causing rise in cholesterol levels. This is also the reason why even strict vegetarians, also have high cholesterol levels. In these populations, intake of dietary fat especially saturated fat in form of ghee, cream coconut is high.

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Various national and international scientific bodies have given the standards of consumption of dietary saturated fats and cholesterol. Most agree that diets should contain less than 7% saturated fats and about 200mg of dietary cholesterol for prevention of heart disease. 

Hence the age-old sensibility “moderation is the key”. It is true in consumption of any food group, especially ones like cholesterol.

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Shilpa Joshi

Mumbai Diet and Health Center
National Vice President, Indian Dietetic Association
Hon. Secretary All India Association for Advancing Research in Obesity

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