What fatty acids do
The fatty acids in oils and fats not only dictate the nutritional properties but also the physical characteristics. The unsaturated fatty acid content of vegetable oils determines their fluidity and other physical and chemical properties of relevance to the food industry.
Oils rich in MUFA are preferred for frying as they are more heat resistant. Oils and fats rich in SFA exhibit higher solid fat content, a property that is required in some food applications (like consistency of fat spreads or formation of layers in pastry), in addition to frying applications.
Oils and fats can also be fingerprinted based on specific nutritional components. For example, palm and rice bran oils contain tocotrienols; palm oil contains beta carotene; rice bran oil contains oryzanol; sesame oil contains lignans; soybean oil contains gama tocopherols; and sunflower oil contains alpha tocopherols. Several oils are projected as healthy oils based on the presence of these nutritional components.
Advice on dietary fat
The UN 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, SFA, MUFA and 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 to take into account the intake of invisible oils and fats.
