I picked up a review copy of this book on the slush pile at work ("Why Women Need Fat") -- the basic hypothesis is that women need more DHA / EPA because they deplete those stores when they get pregnant, because the developing foetus needs extra DHA / EPA for brain formation. So women store DHA / EPA on their hips/buttocks. However, after the first pregnancy, the body stores additional fat on the abdomen so that the second child (who can be bigger than the first, because the pelvic bones are loosened by the first birth) can be even bigger and therefore healthier than the first child.
The authors posit (I think) that women's bodies start accumulating fat on their abdomen in their 30s "just in case" they get pregnant -- the larger child is worth the risk of complications.
However, since the SAD is now weighted toward Omega-6s, our bodies tell us to keep eating more until we get that precious few drops of Omega-3s that we need to store; so if we ate more Omega-3s in the first place we'd get the signal to stop storing fuel sooner. At least, that's how I'm understanding this.
Does this make sense? Ever since reading GCBC, I've been wondering why women, in particular, tend to be more obese in societies where food quality is poor (the Pima, Haiti, etc.) It seems to make sense to me but thought I'd lay this out there for comment from those with more medical background than I have.
asked byMara (355)
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on September 03, 2011
at 03:01 PM
This kind of sloppy science depresses me.
Two phrases jump out and demand reply:
A: "our bodies tell us to keep eating more until we get that precious few drops of Omega-3s that we need to store; so if we ate more Omega-3s in the first place we'd get the signal to stop storing fuel sooner."
Unlikely that we have a specific appetite for omega-3 versus omega-6, since, throughout our evolutionary history, commonly consumed foods containing w-3 tended to contain w-6 and vice versa. Only recently with the mass production of w-6-rich corn and soy did things get out of balance.
B: "women's bodies start accumulating fat on their abdomen in their 30s "just in case" they get pregnant -- the larger child is worth the risk of complications.
The phrase is a blivot of unlikely conclusions.
First, women start accumulating fat at every age, depending on the amount of carb and trans fats in their diet.
Second, there is no evidence that abdominal fat supports the baby's brain growth any more than thigh fat or even a woman's own brain fat. Just because it's in the neighborhood...? Then does the calcium come only from the pelvic bones and spine? OMG.
Third, there is little to no correlation between birthweight and eventual adult height. Large babies would have killed women, which is more than a "complication" it's an evolutionary dead end.
Finally, birth weights were very very uniform until lately. 20% of American women have Gestational DM, and large babies. Those babies don't necessarily grow up to be really tall. Though they are relatively programmed for obesity.
on September 03, 2011
at 12:31 AM
Here is some interesting info from the John D. Speth book. I agree that DHA is accumulated in the buttocks and thighs, but it shouldn't accumulate in the abdominal fat.
If cycling of DHA between adipose tissue and the liver was an important pathway, it would be anticipated that DHA concentration in the adipose tissue would be greater in women than men. This suggestion is supported by the observation that young women have a higher concentration of DPA n-3 and DHA in adipose tissue compared with men???. Bakewell et al. (2006:97???98)
Although maternal diet clearly affects the composition of human milk, these studies using stable isotope methodology show that only a minor proportion of dietary fatty acids is directly transferred into milk, whereas maternal body pools are the major contributors to milk fatty acids, including PUFA and LC-PUFA. Hence, short-term variations of dietary fat composition are buffered to some extent by intermediate incorporation into storage pools, and the PUFA and particularly LC-PUFA content in human milk as well as the supply to the breastfed infant remains relatively constant. It is tempting to speculate that this metabolic buffer benefits the breast-fed infant by reducing the variability in dietary supply of these essential substrates with great biological relevance for early human development. Demmelmair et al. (2001:187???188)
Women also store and mobilize their body fat in ways specifically designed to enhance the availability of DHA and other polyunsaturated fatty acids to the nursing infant. Not only do premenopausal women have more body fat than men, their body fat accumulates primarily in subcutaneous deposits, to some extent in the abdomen but especially in the buttocks and thighs (???gluteal???femoral??? fat). Fat in men, on the other hand, accumulates in visceral or intra-abdominal deposits (Blaak 2001; Das 2006; Koutsari et al. 2008; Lassek and Gaulin 2006, 2007, 2008; Leibel et al. 1989; Mittendorfer 2005; Power and Schulkin 2008; Rebuff??-Scrive et al. 1985; Shadid et al. 2007; Trujillo and Scherer 2006; Wajchenberg 2000; Williams 2004). This difference gives rise to the classic contrast between the ???apple??? or android body shape in obese men versus the ???pear??? or gynoid body shape in obese women. Excess fatty acids stored as visceral fat are readily mobilized in overweight and obese men and have been implicated in the development of a number of diseases, including type 2 diabetes, hypertension, atherosclerosis, and coronary heart disease. In contrast, the gluteal???femoral adipose deposits in women actively accumulate throughout pregnancy but remain highly resistant to being mobilized, except toward the end of pregnancy and especially during lactation (Bird 2003; Blaak 2001; Frayn et al. 2005; Hamdy et al. 2006; Horowitz 2003; Jensen 1997; O???Sullivan et al. 2001; Power and Schulkin 2008; Snijder et al. 2003, 2006; Tan et al. 2004; Wahrenberg et al. 1989; Williams 2004; Yim et al. 2008). - Speth
A main finding of the present study is that the fatty acid composition of abdominal adipose tissue is less favorable than that of buttock. This is in agreement with adult studies indicating elevated proportions of saturated fatty acids and reduced proportions of monounsaturated and polyunsaturated fat in abdominal as opposed to buttock depots???. Mamalakis et al. (2002:1084)
Gluteofemoral fat is richer than abdominal and visceral fat in essential LCPUFAs (Phinney et al., 1994; Pittet, Halliday, & Bateman, 1979; Shafer [sic] & Overvad, 1990), and a lower WHR [waist-hip ratio] is associated with higher DHA levels in the blood (Decsi, Molnar, & Koletzko, 1996; Garaulet et al., 2001; Karlsson et al., 2006; Klein-Platat, Davis, Oujaa, Schleinger, & Simon, 2005; Seidell, Cigolini, Deslypere, Charzewska, & Ellsinger, 1991). In contrast, abdominal fat decreases the amount of the enzyme D-5 desaturase, which is rate limiting for the synthesis of neurologically important LCPUFAs from dietary precursors (Fuhrman et al., 2006; Phinney, 1996), and higher WHRs decrease DHA production (Decsi et al., 2000; Hollmann, Runnebaum, & Gerhard, 1997). Lassek and Gaulin (2008:28)
on September 03, 2011
at 12:01 AM
I'm not going to say that there may not be truth to it, but some of the statements strike me as odd.
Historically, women have done most of their childbearing before reaching their 30s. The idea of waiting until your 30s to start is a VERY recent (and Western) phenomenon. It is plausible that, evolutionarily, a woman in her thirties would be likely to have depleted resources from childbearing and just living, so it could make sense from that standpoint. But the first and second baby would likely be a decade in the past at that point.
I'm not convinced bigger baby = healthier. To some extent, yes. More fat stores improves tolerance to various stressors, and I think CW tends to go a little overboard in their treatment of large babies as an inherent health problem. But there does seem to be a happy medium where most babies do pretty well. On the other hand, it seems reasonable that, when talking about paleolithic people who would be more subject to environmental stressors and presumably wouldn't be frequently growing large babies with blood sugar issues due to gestational diabetes, bigger = healthier would apply.
A person is physiologically capable of passing a larger baby the second time. Often subsequent babies are larger, but I'm not sure there's any evidence that the body is capable of birthing a larger baby during subsequent pregnancies than the first. Again, I can see that it might be true, but I'm really not sure there's any actual support for this theory, or if it's simply hypothesis.
If these things are being stated as fact, I'd want sources.
on September 15, 2011
at 10:05 AM
Since baby is parasite, it will take it from you. Its typical that woman has brain problems (memory, attention...) and skin problems (hard and pocky) without enough DHA.
Babies do not produce delta-5-saturase (or was it 6) that is needed to convert ALA to DHA/EPA. As a consequence, and given that baby is priority, you will suffer. If you started with trans fats in your diet, your ALA to DHA-EPA pathway is completely prohibited so you may be deficient already.
So, take your fish oil, 500mg DHA/EPA per day as long as you are pregnant and nursing. You may also want to give it to baby directly after 6 monhts or so. Aim for high grade oil, moleculary destiled to prevent mercury poisioning.
IMO, this is one of the most important things for healthy baby, along with Iodine (anti cretenism) and Vitamin C (for building baby tissue, for immunity [babies have high limphocite count], for you [improves hospitalisation outomes and recovery and wound healing, prevents SIDS].
on September 04, 2011
at 01:33 AM
But -- is it possible that the reason some of us (particularly women) have trouble losing that last 10-15 lbs is that we're just not getting enough DHA?
on September 03, 2011
at 12:11 AM
Well, Chris Masterjohn argued at one point that DHA and AA (arachidonic acid) are essential and that EPA occurs in fish and doesn't really belong in the mammalian body as it interferes with the body's use of AA. Couldn't say whether that's true or not.