Diet and Exercise

Recommended: Kinivo Bluetooth Headphones

Kinovo Bluetooth headphones

Kinovo Bluetooth headphones – folded

I Occasionally recommend a product I have used and liked with links to the Amazon page — which gives my readers a chance to support this micro-enterprise by buying through it, since Amazon returns a small fee when you do. That doesn’t affect the price you pay, and since I’m a cost-conscious shopper, I recommend mostly cost-effective items.

Kinivo BTH240 Bluetooth Stereo Headphone – Supports Wireless Music Streaming and Hands-Free calling (Black) [Update July 2016] The successor to the headphones I previously recommended for workouts. Great low-cost (c. $25) Bluetooth headphones for exercise, making it easy to use your phone for cordless music while exercising. Good sound, long life battery (I only have to charge mine once a month!), sturdy yet compact when folded, works for phone calls using iPhone or similar.

After my Bose headphones were stolen at the gym, I looked around for a more disposable pair and found the predecessor of this current offering. Good enough fidelity for exercising, and as it turns out they lasted for five years until recently when the left channel wire broke and the ear padding started to erode. The new models are improved but very similar in size and feel, so after a few days of evaluation, I can recommend them.

Soy Protein Blunts Testosterone Response

Soy vs Whey

It’s long been rumored that soy products are similar enough to natural estrogens that males should beware heavy consumption. Bodybuilders especially were concerned that soy protein supplements might be doing them more harm than good. The mechanism for this effect is unclear, but it does seem to exist.

A study (“The Effects of Soy and Whey Protein Supplementation on Acute Hormonal Responses to Resistance Exercise in Men”) from researchers at the Human Performance Laboratory at the University of Connecticut seems to confirm this; from the abstract:

Objective: For many resistance-trained men concerns exist regarding the production of estrogen with the consumption of soy protein when training for muscle strength and size. Thus, the purpose of this investigation was to examine the effects of soy and whey protein supplementation on sex hormones following an acute bout of heavy resistance exercise in resistance trained men.

Methods: Ten resistance-trained men (age 21.7 ± 2.8 [SD] years; height 175.0 ± 5.4 cm; weight 84.2 ± 9.1 kg) volunteered to participate in an investigation. Utilizing a within subject randomized crossover balanced placebo design, all subjects completed 3 experimental treatment conditions supplementing with whey protein isolate (WPI), soy protein isolate (SPI), and maltodextrin placebo control for 14 days with participants ingesting 20 g of their assigned supplement each morning at approximately the same time each day. Following supplementation, subjects performed an acute heavy resistance exercise test consisting of 6 sets of 10 repetitions in the squat exercise at 80% of the subject’s one repetition maximum.

Results: This investigation observed lower testosterone responses following supplementation with soy protein in addition to a positive blunted cortisol response with the use of whey protein at some recovery time points. Although sex hormone binding globulin (SHBG) was proposed as a possible mechanism for understanding changes in androgen content, SHBG did not differ between experimental treatments. Importantly, there were no significant differences between groups in changes in estradiol concentrations.

Conclusion: Our main findings demonstrate that 14 days of supplementation with soy protein does appear to partially blunt serum testosterone. In addition, whey influences the response of cortisol following an acute bout of resistance exercise by blunting its increase during recovery. Protein supplementation alters the physiological responses to a commonly used exercise modality with some differences due to the type of protein utilized.

Blunted testosterone response would be expected to reduce muscle gains from intense exercise. So it appears the widely-held view that soy products and soy protein are counterproductive when trying to build muscle mass is likely correct. The alternative, whey protein, is presumably preferable. Muscle and Fitness Magazine disagrees.

Study: Gut Bacteria on Artificial Sweeteners

Artificial Sweeteners

Since nearly everyone consumes artificial sweeteners in something (toothpaste, protein shakes, diet sodas), there’s impressive coverage of any new study on the topic. This of course is an incentive for the study authors to take their conclusions a bit further than they really should, and the headline writers then compete to jump to even more unwarranted conclusions.

So this Israeli study is everywhere: this writeup, “Saccharin solution? Sugar substitutes may mess with gut bacteria—causing obesity in the process,” from The Economist, is among the responsible ones that carefully mention the context of other studies showing no such effects.

In short, researchers gave mice water with sugar substitutes, sugar, or nothing. These researchers were especially interested in the microbiome and investigated the effects on gut bacteria of the different diets; after a week they dosed them with glucose and noted that the mice on sugar substitutes had higher blood sugar, meaning they had not processed the glucose as effectively (which normally occurs by release of insulin.)

They then killed off the gut bacteria in the mice, and the processing of glucose returned to normal, which supports the theory that the gut bacteria themselves had changed in the presence of artificial sweeteners to increase insulin resistance.

This is very interesting and suggests lots more research possibilities on the influence of our biomes on body processes; it tells us something about mice and artificial sweeteners. But it also reminds us that the response of mice to saccharin was the reason cited to attempt to ban it in the US, but further research in primates showed no significant health concerns at reasonable levels of consumption (though it still tastes bad!)

Reaching for significance (and headlines), the researchers then did something very interesting before publication: they tried to tie their results to human obesity. Noting that some correlation studies show consumption of artificial sweeteners is correlated with weight gain, they suggest the possibility (without claiming it) that human obesity is caused by artificial sweeteners interacting with the gut biome. They recruited 7 (7!) nonusers of artificial sweeteners, gave them maximum allowed doses of saccharin, and observed changes in the gut biomes of 4 of the 7 which looked much like the changes seen in the mice. This result, even if accurate, barely reaches statistical significance.

What can we conclude here? That 90% of human nutrition studies can’t be replicated, meaning no single study means much; that there may well be some very interesting research to be done on the gut flora and fauna, since there are many clues showing the microbiome significantly affects digestive and metabolic processes; that researchers are tempted to direct their results toward headlines which get them notoriety and funding; and that since most studies show reasonable use of artificial sweeteners to substitute for sugar is an aid to weight loss and critical for real diabetics, no one should change their habits because of this study.

Let’s look at the headlines generated by the study:

NYTimes: “Artificial Sweeteners May Disrupt Body’s Blood Sugar Controls”
FT: “Israeli researchers link artificial sweeteners with obesity”
Israel Hayom: “Artificial sweeteners may drive diabetes, Israeli study finds”
ABC: “Study: Artificial Sweeteners May Promote Diabetes”
CBC: “Artificial sweeteners linked to obesity epidemic, scientists say”
WSJ: “Research Shows Zero-Calorie Sweeteners Can Raise Blood Sugar”

Note the better-quality publications (NYTimes, WSJ) avoid sensationalizing the results–it’s especially reprehensible to suggest diabetics should be terrorized and stop using artificial sweeteners, which allow them some semblance of sweetness and have been used for decades without causing problems. The weasel word “linked” in “Artificial sweeteners linked to obesity epidemic, scientists say,” should be a clue to the lack of scientific backing for that headline’s claim.

For further reading, I can recommend the WSJ’s relatively cautious coverage: “Research Shows Zero-Calorie Sweeteners Can Raise Blood Sugar,” by Gautam Naik:

“The scope of our discovery is cause for a public reassessment of the massive and unsupervised use of artificial sweeteners,” said Eran Elinav, a physician and immunologist at Israel’s Weizmann Institute of Science and lead author of the study, which appeared Wednesday in the journal Nature….

They transplanted bacteria from artificial-sweetener-fed mice or sugar-fed mice into other mice that were bred to have no gut bacteria of their own and that had never consumed a sweetener product. They found that the bacterial transfer from the sweetener-fed mice raised the blood sugar levels in the transplant recipients—suggesting that the gut microbes had triggered the higher sugar levels in mice fed fake sweeteners.

Was the same link true for people? Dr. Elinav and his colleagues examined the relationship between long-term consumption of artificial sweeteners and various metabolic measurements in some 380 nondiabetic people.

They found that the bacteria in the gut of those who regularly ate fake sweeteners were notably different from those who didn’t. In addition, there was a correlation between the sweetener consumption and a susceptibility to glucose intolerance, which is a disturbance in the blood glucose level.

Correlation, however, doesn’t necessarily mean causation. In the next experiment, seven volunteers who normally didn’t consume fake sugar were asked to consume products high in the sweeteners. After four days, four of them had significantly higher blood-sugar levels as well as altered populations of bacteria in their gut—an outcome similar to what was seen in mice.

“This susceptibility to sweeteners [can now] be predicted ahead of time by profiling the microbes in the people,” said Eran Segal, a co-author of the study and computational biologist at the Weizmann Institute.

The results need to be corroborated through a study with many more participants.

Our lead author certainly wants to take artificial sweeteners away from people, or at least require prescriptions! Can’t have anything go unsupervised. Such attitudes tend to indicate a less-than-objective scientist.

Here’s a blog post from Suppversity which goes into detail–they have actually read the paper, while I have only seen pieces. Not all the mice suffered ill effects, and the paper’s authors also managed to not publicize the fact that the effects were seen most strongly with saccharin, less with sucralose, and hardly at all with aspartame. So the news trumpeted around the world was (to be charitable) incomplete.

Smarter Babies when Mothers Eat More Salmon

Costco Canned Salmon Filet

… and less vegetable oil. Another correlation study, but it fits a pattern of such studies showing how important omega-3 fats are in building and protecting brains (see “Fish and Fish Oil for Better Brain Health.”) In this case, mothers who ate a diet rich in omega-3s (from oily coldwater fish and some nuts) had higher levels of omega-3s in the breast milk they fed their children, and their children were notably smarter.

Researchers at UCSB and U Pittsburgh have released a study (written up by Science Daily here):

In a paper published in the early online edition of the journal Prostaglandins, Leukotrienes and Essential Fatty Acids, the researchers compared the fatty acid profiles of breast milk from women in over two dozen countries with how well children from those same countries performed on academic tests.

Their findings show that the amount of omega-3 docosahexaenoic acid (DHA) in a mother’s milk — fats found primarily in certain fish, nuts and seeds — is the strongest predictor of test performance. It outweighs national income and the number of dollars spent per pupil in schools. DHA alone accounted for about 20 percent of the differences in test scores among countries, the researchers found.

On the other hand, the amount of omega-6 fat in mother’s milk–fats that come from vegetable oils such as corn and soybean–predict lower test scores. When the amount of DHA and linoleic acid (LA)–the most common omega-6 fat–were considered together, they explained nearly half of the differences in test scores. In countries where mother’s diets contain more omega-6, the beneficial effects of DHA seem to be reduced.

“Human intelligence has a physical basis in the huge size of our brains — some seven times larger than would be expected for a mammal with our body size,” said Steven Gaulin, UCSB professor of anthropology and co-author of the paper. “Since there is never a free lunch, those big brains need lots of extra building materials–most importantly, they need omega-3 fatty acids, especially DHA. Omega-6 fats, however, undermine the effects of DHA and seem to be bad for brains.”

Both kinds of omega fat must be obtained through diet. But because diets vary from place to place, for their study Gaulin and his co-author, William D. Lassek, M.D., a professor at the University of Pittsburgh’s Graduate School of Public Health and a retired assistant surgeon general, estimated the DHA and LA content — the good fat and the bad fat — in diets in 50 countries by examining published studies of the fatty acid profiles of women’s breast milk.

The profiles are a useful measure for two reasons, according to Gaulin. First, because various kinds of fats interfere with one another in the body, breast milk DHA shows how much of this brain-essential fat survives competition with omega-6. Second, children receive their brain-building fats from their mothers. Breast milk profiles indicate the amount of DHA children in each region receive in the womb, through breastfeeding, and from the local diet available to their mothers and to them after they are weaned…. “Considering the benefits of omega-3 and the detriment of omega-6, we can get pretty darn close to explaining half the difference in scores between countries,” he added. When DHA and LA are considered together, he added, they are twice as effective at predicting test scores as either is alone, Gaulin said.

Gaulin and Lassek considered two economic factors as well: per capita gross domestic product (a measure of average wealth in each nation) and per student expenditures on education. “Each of these factors helps explain some of the differences between nations in test scores, but the fatty acid profile of the average mother’s milk in a given country is a better predictor of the average cognitive performance in that country than is either of the conventional socioeconomic measures people use,” said Gaulin.

From their analysis, the researchers conclude that both economic wellbeing and diet make a difference in cognitive test performance, and children are best off when they have both factors in their favor. “But if you had to choose one, you should choose the better diet rather than the better economy,” Gaulin said….

Their results are particularly interesting in 21st-century North America, Gaulin noted, because our current agribusiness-based diets provide very low levels of DHA — among the lowest in the world. Thanks to two heavily government-subsidized crops — corn and soybeans — the average U.S. diet is heavy in the bad omega-6 fatty acids and far too light on the good omega-3s, Gaulin said.

“Back in the 1960s, in the middle of the cardiovascular disease epidemic, people got the idea that saturated fats were bad and polyunsaturated fats were good,” he explained. “That’s one reason margarine became so popular. But the polyunsaturated fats that were increased were the ones with omega-6, not omega-3. So our message is that not only is it advisable to increase omega 3 intake, it’s highly advisable to decrease omega-6 — the very fats that in the 1960s and ’70s we were told we should be eating more of.”

Gaulin added that mayonnaise is, in general, the most omega-6-laden food in the average person’s refrigerator. “If you have too much of one — omega-6 — and too little of the other — omega 3 — you’re going to end up paying a price cognitively,” he said.

The issue is a huge concern for women, Gaulin noted, because “that’s where kids’ brains come from. But it’s important for men as well because they have to take care of the brains their moms gave them.

So not only did the US government’s agricultural subsidies support growing more corn and soybean oils which are negative for brain growth, they recommended diets heavy in carbs, starches, and high-omega-6 vegetable oils that made the population one of the fattest in the world.

Reference:

W.D. Lassek, S.J.C. Gaulin. Linoleic and docosahexaenoic acids in human milk have opposite relationships with cognitive test performance in a sample of 28 countries. Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA), 2014; DOI: 10.1016/j.plefa.2014.07.017

Jeb Kinnison

Writing About Life and Love

Diet and Exercise

Recommended: Kinivo Bluetooth Headphones

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Soy Protein Blunts Testosterone Response

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Study: Gut Bacteria on Artificial Sweeteners

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Smarter Babies when Mothers Eat More Salmon

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