FOOD TODAY 03/2009

Taking a closer look at saturated fat

Emerging research suggests some saturated fats carry out important functions in the body. However, this does not counteract the advice that people should reduce saturated fat consumption.

All fats are made up of glycerol, a fork like structure, and three fatty acids. Fatty acids are made up of carbon, hydrogen and oxygen, arranged as a carbon chain with an acid at one end. Saturated fatty acids contain the maximum number of hydrogen atoms they can hold and no double bonds (whereas unsaturated fatty acids have one or more double bonds). There are several kinds of naturally occurring saturated fatty acids, their only difference being in the number of carbon atoms in the chain.

In practice foods contain a mixture of different types of saturated and unsaturated fatty acids. Table 1 shows common natural saturated fatty acids and typical food sources.

Table 1 Common saturated fatty acids and their typical food sources

Common name	Carbon chain length	Typical food sources (also contain other fatty acids)
Butyric acid	4	Butter, dairy fat
Lauric acid	12	Coconut oil
Myristic acid	14	Coconut oil, dairy fat
Palmitic acid	16	Palm oil, meat and dairy fats
Stearic acid	18	Meat fat, cocoa butter

Saturated fats in the body

All fats, including saturated fats, provide us with a concentrated form of energy. Fats are also essential to carry the fat-soluble vitamins A, D, E, and K into the body, and when deposited in fat stores, they cushion and protect our essential organs.¹

Emerging research suggests that individual saturated fatty acids have their own important biological functions in the body²:

Butyric acid regulates the expression of several genes and may play a role in cancer prevention by stopping the development of cancer cells;
Palmitic acid is involved in the regulation of hormones;
Palmitic and myristic acids are involved in cell messaging and immune function.

Other roles of saturated fatty acids that still require further evidence in humans include:

Myristic acid may regulate the availability of polyunsaturated fatty acids like docosahexaenoic acid (DHA)
Lauric acid may be the raw material for producing omega-3 fatty acids (when omega-3 fatty acids are unavailable in the diet)

Nonetheless, saturated fat can have a great influence on total blood cholesterol and LDL (bad) cholesterol levels, but there are differences in cholesterol-raising effects among the saturated fatty acids.² Effects are generally greater for fatty acids with medium chain lengths (e.g., lauric C12:0, myristic C14:0 and palmitic C16:0) than for those with longer chain lengths (e.g., stearic acid C18:0). Stearic acid does not raise blood cholesterol to the same extent as myristic, lauric and palmitic acids, because it is converted to its mono-unsaturated form (oleic acid C18:1) in the liver very efficiently.

Steps towards a healthier diet

The recommended maximum consumption of saturated fat is ≤10% of calories in the diet.³ The average European is still eating more than this recommended maximum amount of dietary saturated fat, currently about 15% of calories.¹ So attempts to reduce saturated fat intake should continue, ideally paying attention to the fatty acid profiles of different foods.

The main sources of saturated fat in the diet are: fatty cuts of meat, poultry skin, meat products such as sausages and pies, whole milk and full fat dairy products such as cheese and cream, butter, ghee and lard, coconut oil and palm oil, pastry, cakes and biscuits, sweets and chocolate.

Therefore, some ways to decrease the amount of saturated fat in the diet are:

Choose lean cuts of meat and trim off visible fat; remove the skin from poultry meat; grill your meat rather than frying it.
Take care on the amount of sausages, pastry, pies, cakes, biscuits, sweets, chocolate consumed.
Choose lower-fat or reduced fat dairy products.
Choose vegetable oils (rich in unsaturated fat, such as sunflower, rapeseed or olive oil) or fat spread rather than one that is high in saturated fat.

And finally, eat a balanced diet, with plenty of fruits and vegetables and starchy foods (such as rice, pasta, potatoes), and opt for low-fat cooking methods such as boiling and steaming.

References

Facts about Fats – EUFIC Review. Available at: www.eufic.org/article/en/expid/review-fats/
Rioux V. and Legrand P. (2007) Saturated fatty acids: simple molecular structures with complex cellular functions. Current Opinion in Clinical Nutrition and Metabolic Care 10:752-58
WHO Technical Report Series 916 “Diet, Nutrition and the Prevention of Chronic Diseases”. Geneva 2003. Available at: http://whqlibdoc.who.int/trs/WHO_TRS_916.pdf

Terms used in this article

Cholesterol

Fat

Fat-soluble vitamins

Fatty acids

Oil

Unsaturated fat