Swamped with patients who have diabetes and are obese, it is often difficult for physicians to dispense advice on a single food item. For instance, often, we give no specific diktat on edible oils. This is a major gap in clinical care.
Both quantity and quality of the cooking oil is important. There is less controversy about the quantity of oil consumed (including cooking) daily — should be about 3-4 teaspoons daily. An oil-less diet will do harm in the long run since essential fatty acids in oils are required by the body. And, beware, even if a particular diet is touted to be ‘zero cholesterol’, there are likely to be more toxic ingredients within.
Researchers and scientists vary in their opinion about the quality of oils, but some scientific facts have emerged over the past three decades. Remarkable studies done by my colleagues from AIIMS, researching in the USA in the 1980s, showed that one component of fats, monounsaturated fat (oleic acid), when consumed instead of other fats, was highly effective in reducing blood fats and medication in patients with diabetes. While this type of fat is abundant in olive and canola oils, we have used similar mustard oil for centuries (other rich sources are avocados, pistachios, walnuts, almonds and sesame). The astounding success of ‘Mediterranean diets’ in improving almost all health parameters besides improving the condition of diabetics, averting heart disease and increasing lifespan could be due to daily use of olive oils, among other healthy food items (nuts, also rich in monounsaturated fats; veggies, etc).
The second type of ‘good’ fat’ is polyunsaturated fat (one example is omega-3 fatty acids, found in rich levels in fish). One can face hurdles here: fish is often not available and could be contaminated (for example with mercury), and many Indians do not eat fish. In general, levels of these fats are low in the blood of Indians, impacting blood fat levels and heart health adversely. Unfortunately, vegetarian sources of these good fats are few (walnuts, mustard oil, soybean, sesame, peanuts, canola oil, flaxseeds, chia seeds) and contain relatively lesser amounts of omega-3 fatty acids than fish. Disadvantage vegetarians.
The risk of arterial clogging and heart attacks could be extremely high due to intake of saturated fats though some recent opinions vary. A particularly adverse component of saturated fats is palmitic acids (high in palm oil and dairy ghee), which could also increase growth of cancer cells besides acutely increasing risk of heart attacks. Interestingly, taking even one meal full of saturated fat could lead to an explosive break of fats deposited in arteries (“plaque rupture”), which can stop precious blood to the brain, heart or anywhere else in the body within seconds. Unfortunately, and contrary to our traditional belief (“ghee is good for strength and heart and lubricates joints”) and our emotional attachment to it, dairy ghee (different from vanaspati ghee which is partially hydrogenated vegetable oil made from vegetable sources, rated bad healthwise, see below) and coconut oil are replete with saturated fats (60-80%) and palmitic acid, and hence may do harm. Robust scientific studies on ghee are few but one such study shows that a daily intake of even 1-2 teaspoons increases heart attack risk by more than 10-fold! There are animal studies to show that ghee increases the risk of kidney damage and lung cancer as well.
A few small studies which show good effects of ghee (on memory, weight etc) are small and of low scientific power. Similarly, coconut oil has been found to be raising bad blood cholesterol (LDL, prime determinant of blood artery blockages) in six out of seven good studies done till date. It appears that many people do not believe that coconut oil does any harm to the body, basing their opinion mostly on small and poorly executed studies which have little or poor scientific validity. Finally, bhujias and chips widely available in India are made in saturated fat-laden palm oil. Interestingly, many similar snacks (made by the same multinational companies) sold in the USA are made with healthier oils! All saturated fats get deposited in the liver causing its shrinkage (fibrosis and cirrhosis), something we have seen increasingly, Surely, we all need better and more robust research data, and till then should decrease intake of these oils.
One up on saturated fat for increasing heart and liver risks are trans fatty acids, abundant in vegetable ghee (vanaspati and many similar oils available in India). High amounts of trans fatty acids (about 30-40 per cent in some oils) are highly injurious to the heart, liver, pancreas and blood arteries. Indeed, this is the most damaging component of oil among all. Quite interestingly, our research shows that if you reheat foods at high temperatures in any oil, the levels of trans fatty acids progressively increase by 100-200 per cent. These cooking practices are common in Indian households and uniformly adopted by street vendors and most food establishments.
So, how do you stay healthy? Your eyes should be open and scan nutrition labels for the quantity of saturated fats, palm oil, and trans fatty acids. You should consume more fresh fruits and vegetables and taste limited quantities of healthy oils used in rotation and in combination. You should also try not to reuse and reheat any oil.
In the polluted atmosphere that we live in, you certainly deserve one less poison.
(The author is a Padmashree awardee and author of the book “Diabetes with Delight”)
Read More: How to choose a healthy cooking oil? And how much should you consume daily?