News
Vitamin D3 seems to be more effective than vitamin D2
20 September 2013
New research from Norway reports that supplements containing vitamin D3 can increase blood concentrations more effectively than the D2 form.
08 January 2010
A study in human colon cells describes a diet-responsive regulatory network that controls vitamin A production from beta-carotene and intestinal lipid absorption.
Based on the findings (1), the researchers predict that there would be significant differences in beta-carotene utilization in populations with a high versus a low vitamin A status: In vitamin A deficiency, enhanced expression of specific genes in the small intestine ensures that even small amounts of dietary beta-carotene can be efficiently absorbed and used for vitamin A production. When sufficient dietary vitamin A is available, absorption of beta-carotene is blocked preventing excess production of toxic amounts of vitamin A (retinoic acid) making beta-carotene a safe source of vitamin A.
Additionally, the findings imply that dietary vitamin A impacts lipid absorption more generally. A certain vitamin A (retinoic acid)-dependent protein facilitates the intestinal absorption not only of beta-carotene, but also of fatty acids, cholesterol, vitamin E, and other carotenoids.
Vitamin A insufficiency not only is a problem in developing countries but also is widespread in Western society. Approximately 15% of individuals aged 19–24 years in the UK have a total vitamin A intake below the lower recommended intake level (2) and almost half of American postmenopausal women may experience frank or marginal vitamin A deficiency (3).
There is considerable genetic variability in beta-carotene utilization in the general population. Many people have a reduced ability to convert beta-carotene to vitamin A (4). Inadequate supply of dietary vitamin A and/or genetic variability may constitute risk factors for human lipid disorders (dyslipidemia). The role of dietary vitamin A in preventing dyslipidemia associated disorders, such as cardiovascular and neurodegenerative diseases, needs further research and is of unquestionable relevance for human health.
20 September 2013
New research from Norway reports that supplements containing vitamin D3 can increase blood concentrations more effectively than the D2 form.
1 July 2010
"Cognitive decline in the elderly is a significant public health issue. Oxidative stress and inflammation are believed to be involved in the pathogenesis of cognitive decline.
1 January 2013
Despite concerns that have been expressed about possible health risks from high intake of vitamin E, a new review concludes that biological mechanisms exist to routinely eliminate excess levels of the vitamin, and they make it almost impossible to take a harmful amount.