In recent years, there has been increasing interest in the role that specific nutrients may play in helping ensure a healthy pregnancy. In addition to folic acid, another specific nutrient that has been the focus of attention are the so-called ‘omega-3’ fats found in oily fish such as salmon, mackerel and sardine. These fats appear to be important for, among other things, the development of the brain and visual function in the foetus. Consuming plenty of omega-3 fats during pregnancy would seem a worthwhile goal for women keen to give their babies the best start in life possible.
Another potential benefit of omega-3 fats in the body is that they are anti-inflammatory. In theory, then, they may help to reduce any propensity of inflammatory conditions such as eczema. In a recent study published in the American Journal of Clinical Nutrition, researchers in Germany found that higher intakes of omega-3 fats in the last month of pregnancy were associated with a reduced risk of eczema in children at 2 years of age . The apparent protection was small (just 2 per cent), but there was something else about this study that deserves our attention.
In addition to assessing omega-3 intakes, the researchers also measured women’s intakes of so-called ‘omega-6’ fats too. Omega-6 fats including something known as linoleic acid are to be found in foods such as margarine and vegetables oils such as sunflower oil and corn oil. In contrast to omega-3 fats, omega-6 fats tend to promote inflammation in the body. In theory, therefore, higher intakes of these fats would be expected to be associated with an increased risk eczema. And that’s exactly what this recent study found. Higher intake of margarine and vegetable oils were both associated with an increased risk of eczema by about half.
The roughly antagonistic actions of omega-6 and omega-3 fats makes getting a ‘balance’ between them important to health. It is estimated that primitive diets contain a ratio of omega-6 to omega-3 fats of about 1-3:1. However, the fact that we are generally eating far more in the way of omega-6 fats and, almost certainly, less omega-3 too, has led to this ratio increasing to between 10:1 and 30:1 in a typical Western diet.
A glut of omega-6 fat in the modern-day diet may have important implications not just in pregnancy, after pregnancy too. The higher the ratio of omega-6 to omega-3, for instance, the greater the risk of ‘cardiovascular’ conditions such as heart disease and stroke . Other evidence points to a raised omega-6:omega-3 ratio as a potentially important underlying factor in type 2 diabetes . This fatty imbalance has also been implicated in inflammatory conditions and autoimmune disease – conditions where the body’s immune system reacts against its own tissues such as rheumatoid arthritis .
A major source of omega-6 fats are refined vegetable oils that make their way into our food supply in foods such as margarine, fast food, and processed foods such as biscuits, cakes, pizza, pastries and savoury snacks such as pretzels and corn chips. The evidence suggests that the dramatic increase we have seen in our intake of omega-6 fats is a potent force in the rise of many common health issues we now see in industrialised countries. Eating less of these, and more in the way of omega-3 fats, is one nutritional strategy that evidence suggests has relevance to health, whatever our age.
1. Sausenthaler S, et al. Maternal diet during pregnancy in relation to eczema and allergic sensitization in the offspring at 2 h of age. Am J Clin Nutr 2007;85(2):530-537
2. Weber PC. Are we what we eat? Fatty acids in nutrition and in cell membranes: cell functions and disorders induced by dietary conditions. In: Fish fats and your health. Norway: Svanoy Foundation, 1989:9″18
3. Raheja BS, et al. Significance of the n-6/n-3 ratio for insulin action in diabetes. Ann N Y Acad Sci 1993;683:258″71
4. Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids Biomed Pharmacother. 2002 56(8):365-79