Modification of the fatty acid composition of animal-derived foods: Does it enhance their healthiness?

Foods derived from animals are important sources of nutrients for humans. Concerns have been raised that due to their saturated fatty acid (SFA) content, dairy foods may increase the risk of cardiometabolic diseases. Prospective studies do not indicate a positive association between milk consumption and disease risk, although there are few data for other dairy foods. SFA in dairy products can be partially replaced by cis-MUFA (monounsaturated fatty acids) through nutrition of the dairy cow, and while some human randomized controlled trials (RCT) indicate that this may attenuate the effect of dairy fat on plasma low-density lipoprotein cholesterol, there is insufficient evidence to conclude that this will decrease cardiovascular disease risk. Intakes of long-chain n-3 fatty acids (LCn-3 FA) are suboptimal in many countries, and while foods such as poultry meat can be enriched by inclusion of fish oil in the diet of the birds, fish oil is expensive and has an associated risk that the meat will be oxidatively unstable. Other sources of LCn-3 FA such as krill oil, algae, and genetically modified plant seeds may prove to be better candidates for meat enrichment. Also, laying hens have the unusual ability to increase the docosahexaenoic acid in their eggs from being fed plant sources of α-linolenic acid. This suggests a possibly reproduction-related upregulation of the LCn-3 synthetic pathway, the application of which needs more attention. Overall, the health-related value of fatty acid (FA)–modified animal-derived foods cannot be judged by their FA composition alone, although there has been a tendency to do so. More appropriately detailed human RCTs are needed before judgments concerning improved health value can be made.