An article published in the online edition of Daily Mail, "Coconut oil consumption instead of animal fats could reverse cartilage deterioration," has led to a new debate. The article is based on the results of a research suggesting that some fatty acids cause osteoarthritic-like changes in the knees of the rats

Australian scientists from different institutes who studied in this research, examined how the intake of carbohydrates and fatty acids in rats is related to the risk of metabolic syndrome and abdominal obesity as well as joint function.

The rats were divided into six groups according to the source of carbohydrates and fatty acids in their diet. Groups were fed a diet of only corn starch, simple carbohydrates, and various types of fat. The rate of fats to total energy intake was set at 20 percent. The only variable was the source of fatty acids.

According to the results of the research study, metabolic syndrome symptoms appeared in all of the groups except for the rats fed with lauric acid. Rats fed with palmitic and stearic acids, which are long-chain fatty acids than lauric acid, were reported to develop similar changes to osteoarthritis symptoms in their knee joints. It was also reported that this pattern did not appear in rats fed with lauric and myristic acids. Results also indicated that further research is needed to clarify if replacing palmitic or stearic acid with lauric acid in a human diet can prevent osteoarthritis or metabolic syndrome.

How should these results be interpreted?

The research study assesses the effect of different saturated fatty acids on the risk of metabolic syndrome and osteoarthritis in rats. Although long-chain saturated fatty acids (stearic, palmitic acid) were shown more likely to trigger the risk of osteoarthritis than short-chain saturated fatty acids, this effect has not yet been demonstrated in human subjects.

When the media published these results there was no mention that the research was conducted on rats. The media did not report that these effects, which occur in rats, may not apply to humans because of their differing physiological and biological mechanisms.

There is not enough evidence-based data on the preventive effects of lauric acid on metabolic syndrome and osteoarthritis. It is unclear whether rats fed a lauric acid-rich diet develop arthritis due to the preventive effect of lauric acid or the possible deleterious effects of long-chain saturated fatty acids.

What does scientific evidence say?

• The World Health Organization (WHO) recommends that no more than 30 percent of total daily calories should come from fat. In addition, the European Food Safety Authority (EFSA) suggests replacing saturated and trans-fatty acids with mono- and poly-unsaturated fatty acids.

• The World Health Organization (WHO) recommends that no more than 30 percent of total daily calories should come from fat. In addition, the European Food Safety Authority (EFSA) suggests replacing saturated and trans-fatty acids with mono- and poly-unsaturated fatty acids.

• According to a Cochrane review published in 2015, the risk of cardiovascular diseases decreases when saturated fats are replaced with unsaturated fats. However, it is unclear whether replacing saturated fats with monounsaturated fats affects risk of cardiovascular disease. No effects were seen in studies replacing saturated fat with carbohydrate or protein.

References
1. Xiao ve diğ. Saturated fatty acids induce development of both metabolic syndrome and osteoarthritis in rats. Scientific Reports. 2017.
2. http://www.efsa.europa.eu/en/press/news/nda100326?wtrl=01
3. http://www.who.int/mediacentre/factsheets/fs394/en/
4. Hooper L, Martin N, Abdelhamid A, Davey Smith G. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database of Systematic Reviews 2015, Issue 6. Art. No.: CD011737. DOI: 10.1002/14651858.CD011737.