Saturday 25 October 2014
Testosterone is an important hormone for muscle growth and as a result athletes are often interested in optimising levels to improve physical performance and body composition. There are a number of substances that are available as supplements that manufacturers claim to be able to boost testosterone. Such substances include L-aspartic acid, ashwagandha, horny goat weed, royal jelly, tribulus terrestris, ginseng, maca, DHEA and a myriad of other substances. Often scientific studies are cited to support the beneficial testosterone boosting effects of such supplements and these can seem convincing. However, when we delve deeper into the supporting literature we often see that such studies are performed on animals, use unrealistically high doses, are performed on men with sexiual dysfunction, or are simply cell experiments. To be able to ascertain if these substances are really beneficial we should ask two questions. Do the substances raise testosterone levels in healthy humans? And does this increase in testosterone translate into an increase in the amount of skeletal muscle in the subjects?
The answer to both of these questions is usually not so clear cut. Often the testosterone increases are given as relative values, that can appear large, but are in fact of no real world significance. In addition, there are very few studies that show actual muscle building effects of these testosterone boosters. So if you want to boost testosterone to build muscle what are the best options? Well the tried and tested way to boost testosterone to cause skeletal muscle is based on lifting heavy weights and eating a high animal protein diet. These two strategies will cause far more muscle growth that any supplement available on the market and are backed by research done on healthy adults in peer reviewed journals. Lifting heavy weights causes large increases in testosterone as this is the primary way the body will adapt to the stressor, through testosterone induced increases in muscle hypertrophy. A high intake of animal protein producing a positive nitrogen balance is also a proven way to increase muscle mass through increases in testosterone, and the fat content of the meat is partly responsible for this effect.
Dr Robert Barrington’s Nutritional Recommendation: Lifting heavy weights and eating a high animal protein diet are proven ways to build muscle through increases in testosterone levels. Avoiding stress is also important as this is one of the primary ways in which testosterone levels can be diminished. In this regard it is important not to overtrain, as physical activity is a stressor and too much can induce a chronic stress reaction. Adequate rest and sleep is therefore pivotal if this strategy is to work.
Saturday 18 October 2014
The herb rosemary (Rosmarinus officinalis) is actually a member of the mint family, despite its outwardly different appearance. In fact rosemary’s leaves resemble pine leaves more that the lush green leaves of some of the other members of the mint family such as spearmint or water mint. Rosemary is originally from the mediterranean area, where it was a common herb used for culinary purposes in both Ancient Rome and Ancient Greece. In traditional medicine, rosemary is used to strengthen the mind, and this may relate to the presence of its essential oils. In this regard, rosemary is similar to other members of the mint family that are also a rich source of essential oils. However, the composition of the essential oils differ between the members of the mint family and rosemary has some unique oils not found in other plants.
Within the oils in rosemary are powerful antioxidants, which may confer protection from disease. These antioxidants may be a contributory factor in the aforementioned ability to strengthen the mind because antioxidants can prevent lipid peroxidation in the neurones of the brain. Such lipid peroxidation of neurones in the brain is now thought to be a causative factor in degenerative diseases of the brain. Rosemary can also increase blood flow to the head, perhaps because the antioxidants are able to prevent the oxidation that is now thought to cause impaired blood flow due to free radical induced reductions in nitric oxide. One of the antioxidants in rosemary is rosmarinic acid, and studies suggest that rosmarinic acid is able to decrease levels of inflammation which may relate to its antioxidant properties. Rosemary also appears able to stimulate immune function and in this regard may be a useful herb to prevent infection.
Friday 10 October 2014
A high intake of vegetables is associated with improve health outcomes. The exact reason for this is not known, but may relate to the presence of biologically active phytochemicals in plant tissues. Many of these chemicals are secondary metabolites of plants that are absorbed in humans and interact with out biochemistry to cause physiological changes. The flavonoids are such a group of chemicals, but others include the terpenes and the carotenoids. Some nutritionist advocate eating vegetables raw as this prevents the heat of cooking damaging the phytochemicals within the plant tissues. However, evidence shown that some plant chemicals such as lycopene in tomatoes and lutein in spinach are best absorbed following cooking. This likely relates to the fact that heat breaks down the cells walls of the plants and exposes the phytonutrients to our digestive processes. Cooking onions may also increase the bioavailability of the quercetin they contain.
However, it is important to not overcook vegetables, as this may detrimentally affect the nutrient content. A good example of this is broccoli and other cruciferous vegetables. Broccoli contains chemicals called glucosinolates. Broccoli consumption is associated with a reduced risk of cancer because the chemicals it contains can improve detoxification of carcinogens. However, the glucosinolates do not have this effect in their natural state, they much first be converted to isothiocyanates through the action of an enzyme called myrosinase in the plant tissue. This reaction can only happen if the cell wall and internal organelles of the cells are broken open to bring the glucosinolates into contact with the myrosinase enzyme. The heat of cooking is effective at performing this task, but cooking for too long destroys the enzyme and lowers the production of the cancer preventive isothiocyanates.
Tuesday 7 October 2014
Flax Seeds (linseeds) contain high amounts of the essential fatty acid alpha linolenic acid (ALA, C18:3 (n-3)). This fatty acid is the parent compound for production of the series 3 eicosanoids, a group of short lived hormones that regulate important cellular functions including inflammation. Flax seeds are unusual because they are one of the few foods that contains more omega-3 fatty acids than omega 6-fatty acids, and this makes them useful in rebalancing the omega-3 to omega-6 fatty acid ratio. The Western diet for example contains too many omega-6 fatty acids and far too few omega-3 fatty acids and this creates an unbalanced eicosanoid production, which is a primary driver of inflammation and disease. Recommendations to eat flax seeds are therefore often based on their unique fatty acid profile.
However, there is more to flax seeds than the fatty acid profile they contain. Flax seeds are an excellent source of dietary fibre and this may account for some of their health benefits. In addition, the fibre component of flax seeds is associated with a group of polyphenolic compounds called the lignans. These lignans are thought to have particular health effects in humans which may relate to their phyto-oestrogen activity. This ability to interact with the oestrogen receptor may explain the anti-cancer effects of flax seed consumption. This is because flax seed consumption has been shown to reduce oestrogen levels in women and may be able to cause a shrinkage of breast cancer tumours. Of course the tough outer seed coat of flax seeds is indigestible to humans and so milling the seeds is necessary in order to release their nutrients for digestion.
Friday 3 October 2014
L-tryptophan is an essential amino acid. That means without a dietary source, humans die. Amazing then that its sale as a supplement was banned in the United Kingdom and the United States. It is present in most foods in the diet, yet its not allowed to be sold isolated in supplements. The reason for this was that a single batch of L-tryptophan caused a number of deaths because it was contaminated during manufacture. This is unfortunate because L-tryptophan is a very useful supplements to induce relaxation and sleep. This relates to the conversion of L-tryptophan to 5-hydroxytryptophan in the brain, a reaction catalysed by the enzyme tryptophan hydroxylase. Subsequently 5-hydroxytryptophan is decarboxylated to serotonin, a reaction characterised by L-aromatic acid decarboxylase. However, there is another way to get the benefits of L-tryptophan. Supplements of a 5-hydroxytryptophan are available, produced from the Griffonia simplicifolia seed. Once ingested 5-hydroxytryptophan enters the brain where it is converted to serotonin, thus having the same ultimate effect as L-tryptophan. Doses of around 50 to 100 mg are able to induce relaxation by increasing serotonin levels and induce sleep by the subsequent conversion of serotonin to melatonin.