The United States and much of the developed world is experiencing a frightening rise in obesity. Obesity, as we either know from personal experience, or have been told by others, feels awful. It can also contribute to development of a number of conditions that can limit quality of life as well as shorten it considerably. There are probably many different causes, and it is likely that these all contribute in different proportions. But . . . there may be more subtle factors in play. These may include chemicals in the environment and in food packaging and preparation. Check this article for more on that topic. Another simple, but none-the-less insidious, factor may be what have seemed to be minor changes in Westernized diets.
Diet, Omega-3, Omega-6
We may be adept at synthesizing lipids, but what lipids we eat matter too. As most people now know, not all fats are the same. They are not the same for babies either. Two types of lipids have gotten a lot of press and attention over the last years:
- Omega-6’s: these are a family of unsaturated fatty acids with a final carbon-carbon double bond at n-6. (Just what you needed to know.)
- Omega-3’s: these are a family of unsaturated fatty acids with a carbon-carbon double bond at the third carbon from the end. (Who knew?)
We probably don’t even know a tip of an iceberg about the roles they play in our bodies.
Lowering Omega-6 fatty acids during early life lowers body fat later.
At least in mice. Mice whose mothers were fed diets relatively low in Omega-6 fatty acids during lactation had less body fat in adulthood than mice with relatively more Omega-6 fatty acids (Oosting et al. 2010). Mice whose mothers got more Omega-3 fatty acids also tended to have less body fat in adulthood. Body weights were not different. That is interesting. It also supports the idea that having a little more Omega-3 in the diet of pregnant and lactating might result in leaner children. Since obesity has become such a problem in Western cultures this might be good to know. Changes in maternal diet (or reliance on formula rather than breast milk) may be partly responsible for the obesity epidemic.
New research on Omega-3 and Omega-6 fatty acids and infant brain development
This same research group did a follow-up study (Schipper 2013). Mother mice were given diets that were either low in Omega-6, high in Omega-3 or a standard control diet. All diets contained the same proportions of fat, carbohydrate and protein. Just the fat type differed. Results were as follows:
- Pups showed no difference in growth or weight
- No differences in hormones (grehlin or leptin)
- Brains of offspring in both the low Omega-6 and high Omega-3 diets were different from controls.
There were fewer neurons in the brain area that controls energy balance for both groups.
Energy balance refers to energy intake and expenditure. Animals whose mothers were fed either a greater proportion of omega-3s or a decrease in omega-6s showed less connectivity when compared to the standard mouse diet. This study tells us that the fats or oils a mother eats during pregnancy and during breastfeeding alter offspring brain devvelopment. The study was unable to tell us what the change in brain wiring might mean for long-term health and function in people. Or in mice. Hopefully more research will follow.
Schipper L, Bouyer K, Oosting A, Simerly RB, & van der Beek EM (2013). Postnatal dietary fatty acid composition permanently affects the structure of hypothalamic pathways controlling energy balance in mice. The American journal of clinical nutrition, 98 (6), 1395-401 PMID: 24108786
Oosting A, Kegler D, Boehm G, Jansen HT, van de Heijning BJ, & van der Beek EM (2010). N-3 long-chain polyunsaturated fatty acids prevent excessive fat deposition in adulthood in a mouse model of postnatal nutritional programming. Pediatric research, 68 (6), 494-9 PMID: 20724957