SHR

The era of vitamin D as solely a regulator of bone and mineral homeostasis is long-gone. Recent evidence suggests vitamin D to be implicated in numerous chronic diseases and adverse health conditions, including those related to skeletal muscle. In fact, muscle weakness and pain are prominent features of vitamin D deficiency that respond to replacement therapy. It has been shown that vitamin D receptors (VDRs) are present in human skeletal muscle, but the precise mechanisms through which vitamin D exerts its effects in muscle are unclear. It has been previously demonstrated that culturing muscle cells with vitamin D leads to marked cell growth associated with an inhibition of myostatin (the gate-keeper for growth, if you will). More recently, a pilot study in older women with vitamin D deficiency has shown repletion to increase intramuscular VDR expression and muscle fiber size. However, in vivo data concerning the direct effects of the VDR...

MUFAs save lives! … SFAs not so much The European Prospective Investigating into Cancer and Nutrition (EPIC) is one of the largest cohort studies in the world, with more than half a million (521,000) participants recruited across 10 European countries and followed for almost 15 years. In order to determine how substitution of dietary carbohydrates with different fats was related to all-cause and cardiovascular disease (CVD) –specific mortality, Campmans-Kuijpers et al crunched the numbers on the entire EPIC sub-cohort of individuals with diabetes (n=6192). Substituting 5% of calories from carbohydrates with total and saturated fat led to an 8 and 29 % greater risk of all-cause mortality, respectively, but had no effect on CVD-specific mortality. On the other hand, substituting for polyunsaturated fats increased the risk of CVD-specific mortality by 37% and tended to increase all-cause mortality risk by 20%! Keep in mind that no differentiation between types of polyunsaturated fats...

Reducing added sugar intake has become a ubiquitous recommendation by private and public health agencies across the world, and with good reason. Dose-response research has shown that metabolic derangements begin with at least 10% of energy intake coming from added sugars and escalate as the dose increases. Although this research was conducted with high-fructose corn syrup (HFCS), the authors speculate that similar results would be observed if sucrose (table sugar) were used as well because of their similar chemical structure (half glucose and half fructose). Of course, media coverage of the link between sugar and obesity has resulted in a predominant public view that HFCS is particularly detrimental. Whereas sucrose and HFCS are often viewed as detrimental to health, honey has been traditionally viewed as a “natural” sweetener believed to have health benefits other sugars don’t. Sure enough, honey does indeed contain numerous bioactive compounds that may benefit health if consumed...

Have you ever wondered how cooking meat influences its digestibility? It seems like such a simple question – one that should have been answered long ago considering most people eat meat on a daily basis. Alas, it was only recently that Oberli et al from France took to the science to provide an answer. In the first study of its kind, they fed isotopically labelled beef to a small group (n=16) of healthy men and women and followed it through the digestive tract and metabolic pools of the participants. After consuming a standardized diet (1.4 g/kg protein) for one-week prior to the experimental day, in the morning after an overnight fast, each subject was provided 10 minutes to eat 120 grams (27 g protein) of isotopically labelled minced beef steak (mincing reduces the influence of individual chewing efficiency) that was either  fully-cooked meat [FCM; 90°C (194°F) for 30 minutes] or rare...

A major focus of dyslipidemia treatment and prevention of cardiovascular disease (CVD) is the reduction of low-density lipoprotein cholesterol (LDL-c), which is not without good reason. LDL-c has been extensively researched and implicated as a causal factor in the buildup of arterial plaque. Observational data clearly shows that high LDL-c is a risk factor for CVD, but this research also shows that low high-density lipoprotein cholesterol (HDL-c) is a risk factor. Classically, HDL-c is responsible for reverse cholesterol transport, meaning it gathers the cholesterol that could become plaque and brings it back to the liver. Although this role made HDL-c appear to directly counter that of LDL-c, it is now known that HDL-c has many non-classical functions as well, such as anti-inflammatory, antioxidant, and anticoagulant activities. However, it may be that HDL-c is only protective in non-healthy populations, as genetic mechanisms that raise plasma HDL-c do not seem to lower risk...

Lactose Intolerance and the Modern Dairy Industry The principal distinguishing characteristic of mammals is the reliance on mother’s milk during infancy. Notably, the milk sugar lactose provides about half of an infant’s energy demands during this time, and this sugar is nearly exclusively found in milk, begging the question of evolutionary importance. Lactose is a sugar composed of a combined glucose and galactose molecule, both of which play an important role in the biosynthesis of complex carbohydrates, glycoproteins, and glycolipids within most living organisms.  For instance, galactose is one of the six carbohydrates used for construction of gangliosides, which are essential membrane components that play an important role in cell communication and immunity. In order to absorb lactose from the digestive tract, the enzyme lactase is required. Most humans normally stop producing lactase after weening and consequently become lactose intolerant. However, some humans retain this ability, and the importance of this...

Earlier this year I came across a manuscript that argued the current classification of fatty acids, which is based on chemical composition, is inaccurate when discussing health and disease. With 516 references to research evaluating the physiological effects of each fatty acid known to exist, the paper proposed a new classification system for fatty acids that is based upon their biological activity. Although this is a step in the right direction, even the physiological effects of fatty acids are not always absolute. For instance, milk-fat is about 70% saturated fatty acids (SFA) and 30% palmitic acid, which according to the aforementioned manuscript is a fatty acid that does increase one or more cardiometabolic risk factors. However, not all sources of dairy fat have similar effects despite identical fatty acid profiles. A fairly recent review of the influence of dairy products and milk-fat consumption on cardiovascular disease (CVD) risk found that CVD...

Generally speaking, with age comes a natural loss of muscle mass and function that is owed in no small part to a reduction in physical activity. This may be because protein metabolism is greatly influenced by the contractile activity of skeletal muscle, and it has been shown that muscular disuse results in a reduction in muscle protein synthesis (MPS) both after a meal and when in the fasting state. Even modest reductions in muscular loading through step‐reduction (SR; <1500 steps/day) for 2-weeks has been shown to reduce MPS in older adults, further supporting the notion that sedentariness plays a large role in the anabolic resistance of aging. Somewhat obviously, resistance training (RT) is the foundation of any intervention that seeks to counteract muscle and strength loss, and there is no shortage of evidence showing older individuals to benefit. However, many interventions use high-load programs that may not always be feasible for...

The current worldwide obesity problem has gotten to the point that government bodies have considered, and in some cases implemented, taxes on “unhealthy” foods. Although unhealthy is defined differently for everyone, most can agree that sugar-sweetened beverages such as soda would fall under that category, and not without good reason. Certainly Kelly Brownell from the Rudd Center for Food Policy and Obesity, Yale University would agree, as he was the first to propose that a penny-per-ounce excise tax could reduce consumption of sugared beverages by more than 10%.  This begs the question, what type of taxation would be most effective? There are essentially two types of taxes: inclusive and exclusive. The former means that the tax is included in the list price so that a $1.00 item with a 10% tax would show $1.10 on the price tag, while the latter is the standard sales tax whereby the tax amount is...

Metabolically healthy obese – key protective factors Obesity is commonly accompanied by numerous comorbidities (metabolic syndrome) that involve insulin resistance (IR), type-2 diabetes (T2D), hypertension, dyslipidemia, cardiovascular diseases, and a systemic inflammatory state. However, not all obese adults have these conditions and there are in fact obese individuals who have less visceral fat and adverse health complications than would be expected, a condition that has been termed metabolically healthy obesity (MHO). Why are these people different? That is the central question answered by Goncalves et al, who reviewed the protective metabolic, genetic, and etiological factors of MHO that represent between 10% and 45% of the adult obese population. It turns out that everything is traceable to one seminal factor – lower visceral fat, which is what ultimately causes IR and the detrimental inflammatory and hormonal profile that contributes to increased risk for cardiovascular disease. Whether some individuals carry genetic predisposition to MHO,...