Reduced bone mineral density, altered calcium homeostasis (regulation and
equilibrium of calcium levels and function) and increased risk of hip fracture
are all seen after a stroke. A deficiency of vitamin D is well documented in
long-term stroke survivors. In this study the levels of vitamin D were checked
in patients who suffered a first acute stroke (acute means sudden and severe).
44 acute stroke patients had their serum vitamin D levels checked and compared
to 96 healthy-elderly subjects. The stroke patients had less vitamin D than the
healthy elderly with 77% of the patients falling in the insufficient range. The
study was performed at Addenbrooke's Hospital, Cambridge, UK, and is published
in the January 2006 issue of Stroke, a journal of the American Heart
Association.
Commentary by Jerry Hickey, R.Ph.
Recent research with vitamin D shows that it is low in the elderly with
osteoporosis and also in the elderly with hip fractures. Having sufficient
vitamin D reduces the risk of falling in the elderly, reduces the risk of
osteoporosis, reduces the risk of fracture, and has been shown to improve
strength.
Protein supplementation supplying branched chain amino acids may decrease
mental fatigue during prolonged exercise
Recently it has been shown that serotonin levels increase in the brain during
endurance exercise and this leads to mental fatigue. serotonin is made from the
amino acid L-tryptophan. Branched chain amino acids (BCAA) are large neutral
amino acids just like L-tryptophan and just like L-tryptophan they enter the
brain via the same mechanism and therefore under normal circumstances compete
with L-tryptophan for absorption (the BCAA are Leucine, Isoleucine and Valine).
During exercise the BCAA are used as fuel by the muscles and are not available
to compete with L-tryptophan to decrease its entry into the brain (and this is
what contributes to the mental fatigue; the unchecked absorption of l-tryptophan).
Oral supplementation with a protein improves BCAA levels and this in turn allows
competition with L-tryptophan decreasing its absorption into the brain,
decreasing the formation of serotonin and delaying central fatigue. The study
was performed at Morton College, Oxford, UK, and the University College of
physical Education and Sports, and the Department of Physiology and Pharmacology
at the Karolinska Institute, Stockholm, Sweden and is published in the January
2006 issue of the Journal of Nutrition
