Delivering on Dietary Fat Guidelines
The Food and Agricultural Organisation (FAO), World Health Organisation (WHO), US Department of Agriculture, EURODIET, Spain, Germany, UK, the Netherlands, Australia, New Zealand and India are among organisations or countries that offer recommendations on consumption of total fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) as a part of dietary guidelines.
It is important to keep in mind that these dietary reference values are derived for population groups and not for individuals, whose needs vary depending on personal and lifestyle-related factors. Recommendations vary considerably because some authorities focus on avoiding deficiencies, while others aim to prevent chronic diseases.
One challenge is to translate research findings for different health-related outcomes – such as heart disease, cancer or mortality, with varying consumption levels being beneficial or harmful – to population-based recommendations.
Most organisations, including the FAO and WHO, place the required total dietary fat intake in adults at between 20-35%E. They advise that 20-35% of the total daily energy intake should come from dietary sources of oils and fats. The upper limit for fat intake is to ensure that people do not consume too many daily calories as fat, since it is the most energy-dense macronutrient.
In general, normal-weight women/men should aim for daily energy equivalent of about 2,000-2,500 kcal; of this, they should consume 20-35%E from total oils and fats, which is equivalent to 44-78gm/55.5-97gm of oils and fats.
But there is a parallel need to consider the intake of invisible oils and fats. These are consumed via nuts, vegetables, sweets, snacks, ice cream, pickles, baked goods, coconut, meat, cheese, cream, milk and cereals.
The small amounts of invisible oils and fats add up to a substantial level in the daily diet – up to at least 15gm in the rural population and 30gm among urban middle-income and high-income groups in India, according to the National Institute of Nutrition in Hyderabad. This figure may vary from country to country depending on food consumption habits.
According to some health organisations, the recommended daily intake of visible oils and fats is about 25gm for a sedentary adult male and about 20gm for a sedentary adult female. However, this should be adjusted based on intake of invisible oils and fats.
Intake of fatty acids
The recommendations for total fat intake are subdivided for specific fatty acids. Several organisations suggest keeping SFA consumption below 10%E.
However, a meta-analysis published in the British Medical Journal in 2015 found no association between high levels of saturated fats in the diet and coronary heart disease (CHD); and no association was found between saturated fats consumption and other life-threatening diseases like stroke or type 2 diabetes.
It is trans fats that are associated with all-cause mortality, total CHD and CHD mortality. Due to this, the recommendation is to restrict intake to below 1%E.
The recommended PUFA intake ranges between 5% and 12%E. However, some set recommendations for specific PUFA including Omega-3 fatty acids like alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); and Omega-6 fatty acids like linoleic acid (LA) and, in some cases, also arachidonic acid.
The recommendation for LA (Omega-6) is about 1-10E%, with the FAO/WHO advising 2.5-9%E. For ALA (Omega-3), the recommendation is 0.2-2E%, with the FAO/WHO advising about 2%E. For EPA/DHA, most organisations recommend 0.25-2gm per day.
The majority of dietary recommendations do not have specific advice for MUFA, although there is an indication of 10-20%E by the FAO.
Blending oils for balance
All the fatty acids should be consumed in a balanced manner to prevent deficiency symptoms. Unfortunately, no single vegetable oil or fat can meet all the nutritional and dietetic requirements with a well-defined fatty acid balance.
The solution lies in the blending of oils to provide the proportionate requirements of SFA, MUFA and PUFA. One of the best combinations to obtain the required balanced fatty acid composition could be palm oil and soybean oil in equal proportions.
Soybean oil provides Omega-3 fatty acids. Palm oil contains 40-45% SFA (palmitic acid), 35-40% MUFA (oleic acid) and about 10% PUFA (linoleic acid). Whenever MUFA- or PUFA-rich oils have to be balanced with SFA, palm oil is the only optimum source of SFA. It is also a natural substitute for hydrogenated oils that create trans fats.
In addition, palm oil contains unique nutraceuticals such as beta carotene and tocotrienols along with tocopherols and squalene. Tocotrienols are isomers of Vitamin E and are known to exhibit powerful antioxidant properties with anti-inflammatory effects. They also impact lipid metabolism via a key regulatory enzyme.
Dr RBN Prasad
Platinum Jubilee Mentor & Former Chief Scientist
Centre for Lipid Research
CSIR-Indian Institute of Chemical Technology