Science Headlines Pertaining to Food Stuffs:
• “Mind Over Milkshake.” A study originally published in 2011 looking at the psychological control of hormone release has been garnering a lot of media attention as of late and is worth noting. The study demonstrated that food of the same nutritional content, but bearing different labeling, can affect ghrelin production and satiety. Specifically, when people consumed food they believed was more “indulgent,” they had a steeper decline in the hormone ghrelin, causing them to feel a greater sense of satiety. They also found that food labeled as lower-calorie did not affect the ghrelin response.
• “Is your high protein diet “as dangerous as smoking?” In early March, a sensational news headline touting that high protein diets were as harmful as smoking circulated the internet and health blogs. The headlines spurred from a primary research article published in Cell Metabolism and a corresponding news piece published on the USC News website.
The initial barrage of news articles claiming high protein diets were as harmful as smoking quickly included popular news sources including The Independent, and The Guardian. The claim has since been termed a “triumph of PR spin” and review of why things got out of hand was written by Nicky Ryan. The NHS also published a good recap of the article and the hype surrounding the article.
• “Early Americans ate more meat than you think.” A recent article highlights the work of investigative journalist Nina Teicholz, author of The Big Fat Surprise. The article questions the common conception of dietary habits of early Americans as being low-meat and high in vegetable content, a commonly cited “fact” to support the low-fat diet industry and government recommendation on food choice.
• Rice vs. Wheat. For the past two decades, differences in the psychology of East Asian and West Asian peoples have been noted. Qualities of East Asians tend to include more interdependency and holistic thinking, while West Asians tend to be more independent and analytical.
It has been hypothesized that as capitalism, education, and wealth become more prominent features of society, it fosters independence and analytical thinking. Another leading hypothesis is that pathogens in the environment can drive populations to be more “insular” (the so-called pathogen prevalence theory).
A recent paper challenges these hypotheses, however, and proposes a different alternative: that differences in rice versus wheat farming can explain the psychological differences found. The idea is that rice farming requires more interdependence and cooperation, in part because it is more difficult to grow and requires these traits. Conversely, wheat is relatively easy to grow and requires little cooperation. These differences are proposed to explain the psychological differences in interdependent versus independent thinking in rice versus wheat farming societies in China.
A mother’s milk differs for boys and girls. Understanding these differences may lead to infant formulas that are specific to a child’s sex.
Science Headlines Pertaining to All Things Old:
• Paleo Ale. Lost Rhino Brewing Company is now offering a “Paleo Ale” made from yeast growing on a 35-million-year-old fossil.
• Ancient teeth reveal a wealth of information. Dental calculus once again proves to be a rich source of archeological information. In a recent nature publication, scientist Christina Warriner describes a myriad of information associated with dental calculus including periodontal disease pathogens (and associated antibiotic resistance genes), dietary habits, and the immunological profile of the host. In a related study, scientists investigate ancient poop and find some surprising results.
• Stone Age Hunter-Gatherers. Transition to farming in Scandinavia occurred ~6,000 years ago. A recent report about two Neolithic Scandinavian populations – one hunter-gatherer and one farming – suggests non-symmetric gene-flow into the farming population and a low level of genetic diversity among the hunter-gatherer population.
Science Headlines Pertaining to Your Bacteria:
• No Soap Experiment. In the Ancestral Health Movement, people have been murmuring about the appropriate use of soaps, hair products, body washes, face washes, and the use of other personal hygiene products for quite a while. The Paleo Mom has been outspoken about her decision to give up hair washing, Richard Nikoley of Free the Animal fame hasn’t used soap in 4 years, and there are more than a few threads discussing the issue on the PaleoHacks forums.
I mean, we’re all about supporting a healthy microbiome in and out, right? Doesn’t washing with soap get rid of all the good bacteria, too? While there are some who brave the no-soap-washing experience, more than a few are skeptical (or, maybe just a little OCD). For those who don’t want to give up lathering up, or for those who are looking for a healthier way to do it, there may be an answer. A recent NY Times article highlights the experience of Subject 26 in a clinical trial for bacterial soap headed by AOBiome, the patented technology incorporates the bacteria N. eutropha which oxidizes ammonia and acts like a “built-in cleanser, deodorant, anti-inflammatory and immune booster.”
In a related study, Triclosan (a common ingredient in many soaps) was found to promote the colonization of Staph. aureus in the nasal cavity.
• Less is more. Feeling conflicted that your diet isn’t filled with many varieties of plants and meat from different sources? The lack of food diversity may not be as bad as you might assume. A recent study published in Ecology Letters demonstrates that (in fish) an increased dietary diversity can actually reduce the diversity of the gut microbiome. Diversity in the gut microbiome is generally regarded as a positive for a variety of health outcomes, with less diversity being associated with chronic and inflammatory disease. Maybe eating the same thing every day isn’t so bad, after all.
• Bacteria in human placenta. Remember being taught that infants were born sterile? This dogma has been increasingly questioned in the past few years, and the final nail-in-the-coffin is here. A recent study has demonstrated (by bacterial sequencing) that there is a placental microbiome which most closely resembles the oral microbiome of the mother.
Poor oral health during pregnancy has been linked to a variety of complications including pre-eclampsia, gestational diabetes, preterm births, low birth weight, and fetal loss. While these associations have been documented for quite some time, these new studies give some insight as to why we see those associations.
• The Guts of Present Day Hunter-Gatherers. The Hazda are unique people – they are reported to be the last population of modern-day, full-time hunter-gatherers in Africa. We previously reported on the research of Jeff Leach, a scientist striving to understand the microbiome of the Hazda population.
A recent analysis of the intestinal microbiome of the Hazda generated some surprising findings. It could be expected that they have a unique microbiome, which they do, but what is more surprising is that the Hazda appear to have high levels of Treponema, which are generally associated with the disease, and low levels of Bifidobacterium, which are often associated with health. Notably, high-fat diets are known to reduce Bifidobacterium, and this is often cited as a reason to avoid a low-carb high-fat diet.
Importantly, “we must redefine our notions of “healthy” and “unhealthy” bacteria since these distinctions are clearly dependent on the environment we live in.”
• Antibiotics and autoimmunity. A recent report identifies the ability for antibiotics to induce stop codon readthrough and generate self-peptides that can be recognized by T cells of the immune system. This allows T cells to recognize self-proteins, and potentially respond in an autoinflammatory way, particularly if coupled with an inflammatory “danger-signal.” Further research will investigate if antibiotic usage (particularly a class of antibiotics including gentamicin) is associated with autoimmune disease.
Headlines Pertaining to Sleep, Hormones, and Your Brain:
• Lactose intolerance and hypothyroidism. Gastrointestinal disorders are often associated with hypothyroidism and a need for exogenous thyroxine supplementation due to intestinal malabsorption of exogenous hormone. A recent study investigated individuals with lactose intolerance and demonstrated that lactose intolerance contributed to a need for increased thyroxine (i.e. hypothyroidism). Of note, only about 30% of the adult population maintains high lactase expression and remain lactose tolerant past infancy.
• Are children more sensitive to light at night? A recent study published in the Journal of Clinical Endocrinology and Metabolism reports that children may be twice as sensitive (as indicated by suppression of melatonin production) to nighttime light compared to adults. Parents now may be the time to stock up on orange glasses. A related study published in March showed that melatonin as a dietary supplement can help to defray the effects of age-related bone loss.
• Sleep Loss Damages Neurons. A recent study demonstrated that increased sleep loss can lead to neuronal damage in the locus coeruleus due to a reduction in Sirtuin type 3 production in mitochondria.
• When Stress is Good For You. A study published in Nature reports that a protein called REST, which is homeostatically upregulated during cellular stress, is reduced in Alzheimer’s disease and dementia.
• Biomarkers for depression. Higher serum levels of cortisol have been proposed as a biomarker for depression in boys.
• Sleep deprivation and the HPA axis. Poor sleep quality has long been associated with negative health consequences. A recent study looked at sleep restriction and it’s a relationship with cortisol. The study demonstrates elevated morning ACTH (but not elevated cortisol) following sleep restriction with an increase in evening cortisol (without elevated ACTH levels). These alterations also increased appetite, but not perceived stress.
• Intermittent Fasting. Intermittent fasting (IF) has been often heralded in the ancestral health community as a way of increasing weight loss and metabolic performance, though many have voiced concerns (1, 2, 3). A new study published this month in Endocrinology demonstrates that extended 24 cycles of IF actually induces overeating behavior (possibly caused by increases in the hypothalamic hormones AGRP and NPY), higher metabolic rates on feeding days, and enhanced lipid oxidation on fasting days.
However, they also demonstrate that IF preserves leptin sensitivity, in a way that ad libitium feeding did not. Furthermore, the authors found that IF increases orexigenic signaling and decreases thyrotropin-releasing hormone (TRH), leading to a lower energy conversion efficiency, thereby resulting in lower weight gain.
• Young Blood. Parabiosis – where two organisms are joined to share physiological systems – seems like a thing of science fiction and horror movies. In fact, it’s an incredible way to study the factors found in one system of a particular organism, and ask how it might affect the physiology of another.
In this example, the circulatory system of a young mouse was joined with the circulatory system of an aged one. The results of a recent study indicate that young blood might be good for you (well, at least for mice). Scientists have confirmed previous reports that young blood can rejuvenate not only the heart but also skeletal muscle and neuronal tissue in aged animals. The apparent culprit is a protein called GDF-11 (growth differentiation factor 11).