Choose the right cooking oil in diabetes

Dr. Saptarshi Bhattacharya, Senior Consultant, Apollo Centre for Obesity, Diabetes & Endocrinology (ACODE), Indraprastha Apollo Hospitals, Delhi

The author would like to thank Puja Dutta, Senior Nutritionist and Diabetes Educator, Indraprastha Apollo Hospitals, Delhi, for her inputs. 

 “Which cooking oil is the best for diabetes?” is a commonly asked question. With varieties of edible oil in the market, and almost all claiming to be the healthiest, it’s natural to get puzzled. An internet search on the topic will lead to millions of hits and perplex you even more. So is there any such magic oil that can lower blood sugar and prevent heart attack? An even more intriguing dilemma is how much of it is safe. What do the medical literature and current evidence suggest?

Different types of fats and oils

The constituent fatty acids determine the character of the oil and health impact. Fatty acids belong to four varieties – saturated fatty acid (lacks double bond), monounsaturated fatty acid or MUFA (contains one double bond), polyunsaturated fatty acid or PUFA (two or more double bonds), and trans-fatty acid (double bond present in trans configuration). 

Health hazards of trans-fat

Trans-fats are primarily synthesized industrially by partial hydrogenation of unsaturated fatty acids. Ingestion of trans-fat has a negative bearing on health. It raises LDL (bad) cholesterol and lowers HDL (good) cholesterol and is estimated to cause 500,000 heart disease-related deaths annually. Longer shelf life, low cost, and easy cookability make it a preferred manufacturer choice. 

In May 2018, the World Health Organization (WHO) called for the abolition of industrially-manufactured trans-fat by 2023. The WHO’s REPLACE action framework urges that countries implement best-practice policies to limit trans-fat to 2% of oils and fats in all foods. 

Hydrogenated or partially hydrogenated fat in the ingredients label implies the presence of trans-fat. Such foods include vegetable-based ghee (vanaspati), margarine, and many commercially baked and deep-fried foods. Check the label for trans-fat in pre-packaged foods (e.g., snacks, cakes, cookies, biscuits, doughnuts, and wafers).

Health impact of saturated fatty acids

Foods such as butter, ghee, cheese, red meat, palm, and coconut oils are rich in saturated fat. Oils containing saturated and trans-fat are solid or semi-solid at room temperature. Saturated fats increase LDL levels, the component of cholesterol that has the potential to clog the blood vessels. The WHO recommends keeping saturated fat consumption to less than 10% of total calories. 

Health benefits of monounsaturated and polyunsaturated fatty acids

MUFA and PUFA are beneficial and if used in place of saturated fat, decrease the chance of heart problems. MUFA is present in olive, canola, peanut, safflower, mustard, and sesame oils, avocados, almonds, and cashews. 

PUFA has two principal varieties – omega-3 and omega-6 fatty acids. These essential fatty acids must be supplied through diet as the body cannot synthesize them. Omega-3 fatty acids are most abundant in fish and seafood, seeds and nuts like chia seeds, flaxseeds and walnuts, soya bean, and canola oil. Oils containing omega-3-fatty acids have been extensively studied for their health benefits. Theoretically, they have anti-inflammatory and cardio-protective actions. Still, clinical trials of medically supplementing it provides minimal additional benefits. Omega-6 fatty acids, the other variant of PUFA, can be obtained from oils of soybean, sunflower, safflower, and corn. 

How much oil should be consumed 

Energy intake has to be balanced as per energy expenditure and weight. Fats and oils are rich in calories (9 calories/gram), and excessive consumption will lead to weight gain. Even though MUFA and PUFA are healthy, their benefits are observed when ingested as saturated and trans-fat substitutes. 

The amount of dietary fat ideal for diabetes is still a controversy. The WHO recommends restricting fat intake to less than 30% of total calories. However, diets containing very low carbohydrate and large quantities of fat, such as the keto diet, are getting popular. These diets offer promise in the management of obesity and diabetes, but long-term sustainability remains a challenge. The recently published American Diabetes Association 2022 guidelines suggest that the distribution of fats, proteins, and carbohydrates should be personalized according to an individual’s eating patterns, preferences, and health needs. 

Which oil should we choose

Evolving evidence suggests that rather than the total quantity, the type of fat being eaten is more critical. We should definitely avoid trans-fat. Saturated fats such as butter, ghee and, coconut oil should be preferably replaced with oils rich in PUFA such as sunflower, soybean, canola (rapeseed), corn, and safflower oils. There is however little data to suggest that one is better than the other among these. Apart from a balanced diet with the right type and amount of oil, a regular exercise schedule, timely medication, and periodic check-ups are fundamental to healthy living in diabetes. 

Tips to healthy fat consumption in diabetes

Composition of commonly used edible oils and fats per 100 gram (there are variations according to brands and subtypes)

Composition can vary slightly according to subtypes

Erucic acid present in mustard oil is a MUFA but still might have an undesirable effect on the heart in high quantities

Varies from brand to brand