B vitamins Part 2
Integrative and Functional Medical Nutrition Therapy by: Diane Noland, Jeanne A. Drisko, Leigh Wagner
Homocysteine was mentioned in our previous blog and this blog will continue on with it! Elevated plasma homocysteine levels can be due to renal insufficiency, deficiencies of folate, vitamin B12, vitamin B6 and vitamin B2. Iron deficiency should always be taken into account when assessing folate and B12 status. Elevated homocysteine and low levels of vitamins B12, B6, and folate have also been associated with bone loss and structural deterioration of bone tissue. Deficiency of vitamin B12 is associated with lower blood levels of osteocalcin and alkaline phosphatase and may point to the activity of osteoblasts and bone metabolism being affected by vitamin B12 status. Deficiency of even one B vitamin will negatively affect the ability to generate energy in the cell. The active forms of thiamine, riboflavin, niacin, and pantothenic acid are essential coenzymes in the mitochondria to make adenosine triphosphate (ATP), the cell’s energy currency. Thiamine plays a role in the synthesis of fatty acids, steroids, nucleic acids, and aromatic acid precursors and in the synthesis of neurotransmitters and bioactive compounds essential for brain function. Thiamine also plays a neuromodulatory role in the acetylcholine neurotransmitter system and can relieve fatigue associated with hypothyroidism. Thiamine can be deficient in grain-free diets and depleted with high intake of alcohol. Thiamine also plays a role in glucose metabolism. Riboflavin is required for the synthesis of two flavoprotein coenzymes. The flavoproteins are also involved in fatty acid metabolism in brain lipids, the absorption and utilization of iron, and the regulation of thyroid hormones. Clinically, higher doses of riboflavin at 400 mg are helpful with preventing migraine headaches. Niacin's are critical for enzymes involved in every aspect of peripheral and brain cell function. Pantothenic acid is required for the synthesis of coenzyme A (CoA). CoA plays a role in oxidative metabolism and contributes to the structure and function of the brain via its role in the synthesis of cholesterol, amino acids, phospholipids (PLs), and fatty acids. Vitamin B6 plays an essential role in the folate cycle and amino acid metabolism and is a rate-limiting cofactor in the synthesis of neurotransmitters including dopamine, serotonin, GABA, noradrenaline, and the hormone melatonin. When GABA is unable to participate in its inhibitory role on neural activity, disordered sleep, behavior changes, cardiovascular function, and loss of hypothalamus–pituitary control of hormone secretion can result. Low B6 status has been found in oral contraceptive users, smokers, and people with celiac disease, alcoholism, and diabetes. Vitamins B6, B8, and B12 have been shown not only to reduce psychiatric symptoms but also shorten the duration of illness. Vitamin B12 is protective against neurological deterioration, and deficiency of B12 is associated with peripheral neuropathy, cognitive impairment, and neurodegenerative disease. Causes of B12 deficiency are largely related to absorption in the GI tract, lack of intrinsic factor, or dietary deficiency such as with vegan diets. Autoimmune pernicious anemia, intestinal surgery such as bariatric surgery, and chronic gastritis from H. pylori infections all decrease the release of intrinsic factor which can result in B12 malabsorption. Undiagnosed celiac disease can also result in malabsorption of B12. Metformin decreases serum B12. Proton pump inhibitors and other medications that reduce the production of hydrochloric acid are also associated with B12 deficiency. An effective test for B12 sufficiency is MMA in blood or urine. The take-home message with B vitamins is to supplement all the B vitamins (not just one) because they work synergistically.
