Vitamin D is known as a fat soluble vitamin. However, we have learned that it is actually a prehormone with extensive physiological effects. It is available in two forms: ergocalciferol, vitamin D2 and cholecalciferol, vitamin D3. Ergocalciferol (VitD2) comes from ergosterol, a plant sterol and yeast. Cholecalciferol VitD3, is synthesized in the skin via 7-dehydrocholesterol, a cholesterol precursor. Both forms are biologically inert (inactive) until they are hydroxylated (converted) in the body to Calcitriol.
Hydroxylation (conversion) of Vitamin D to calcitriol occurs in the kidneys. People with kidney failure may require Vitamin D in its active form. Vitamin D3 is significantly more potent and effective in humans.
Few foods naturally contain Vitamin D and the ones that do have been fortified. Brief exposure to sunlight is the best way to get Vitamin D. Skin exposure to the sun provides as much as 80% to 90% of the body's Vitamin D stores. In northern latitudes sun exposure particularly in the winter months may not be sufficient to cause Vitamin D synthesis in the skin. Sunlight intensity depends on latitude, altitude, season, cloud cover, ozone levels, etc. The capacity of UVB mediated Vitamin D synthesis is huge. Six days of casual sunlight exposure without sunscreen can make up for 49 days of no sunlight exposure. Skin pigmentation affects Vitamin D synthesis. A light-skinned person in northern latitudes wearing a bathing suit receives about 10-20,000 units of cholecaliferol in 10-12 minutes of peak July sun. A darker skinned person would require 30 minutes and an African-American 120 minutes for their skin to produce the same amount of Vitamin D.
African-American infants who are exclusively breast fed are at higher risk for Vitamin D deficiency and Rickets. Sun exposure three times a week for a period of time ( 25% of that which would cause a mild sunburn) will produce adequate amounts of Vitamin D.
Factors that affect Vitamin D levels:
Insufficient sun exposure
Reduced skin synthesis
Lower dietary intake
Impaired intestinal absorption
Decreased metabolism by the kidneys to active form of Vitamin D
(this condition increases with aging)
Vitamin D receptors decrease with age (serious concern for the elderly)
Obese people may have reduced serum Vitamin D levels and reduced
bioavailability. It seems the Vitamin D is sequestered into body fat
and unavailable.
Vitamin D regulates serum calcium and phosphorus concentrations. It enhances the efficiency of the intestinal absorption of calcium. Calcitriol (active form of Vitamin D), also has effects in the brain, heart pancreas mononuclear cells, activated lymphocytes, and skin.
Vitamin D increases muscle strength and neuromuscular function in addition to strengthening bone. It increase protein synthesis (700-800 units/day).
Vitamin D seems to have immunosuppressant activity, beneficial in autoimmune disorders like Rheumatoid Arthritis and Multiple Sclerosis. Evidence suggests that it improves respiratory disorders. There is an association between levels of 25-hydroxy vitamin D serum levels and pulmonary function. It might be involved in remodeling lung tissue. It could also decrease immune mediated inflammation in the airway.
Vitamin D deficiency is linked to an increase risk of falls. Taking Vitamin D supplements reduces falls by 22% in the elderly. Some studies showed that this benefit is independent of calcium supplementation.
A dose of 800units or higher is necessary for it to be effective. Interestingly, researchers believe that Vit D prevents falls by decreasing body sway and decreasing systolic blood pressure rather than increasing bone mass strength. Until now Vitamin D has been seen as a mere adjunct to calcium supplementation, but it is necessary and effective in it's own right.
Studies show that individuals with higher levels of vitamin D serum levels (25mol/L) concentrations have a significantly lower incidence of certin cancers, particularly gastrointestinal. In clinical trials, women taking calcium (400-1500mg/day with 1,100units of vit D3 had a 60% lower risk for developing cancers of various types.
Long term vit D supplementation decreases the risk of Multiple Sclerosis in women by 40%. Again the effect is dose dependent in this case a minimal dose of 400units/day. In addition, when vit D levels were measured in the general population the higher the level the lower the chances of developing Multiple Sclerosis (50nmol/L). Scientists suspect that this may be one of the reasons why the rate of MS is higher the further you are from the equator.
A large trial showed that women with lower levels of vit D have a higher risk of being obese, yet another reason to take vit D. When combined with calcium it helps maintain a healthy weight baseline. Effective doses are between 800-2000units/day.
Cautions: If you are using topical vitamin D creams you must consult your physician before taking vitamin D orally. Topical vitamin D is absorbed. Cimetidine (Tagamet) can decrease active vitamin D levels, particularly in patients with liver or renal insufficiency.
Showing posts with label Information of Vitamins/Supplements. Show all posts
Showing posts with label Information of Vitamins/Supplements. Show all posts
Monday, January 28, 2008
Omega-3: "An Omega a Day Helps Keep the Doctor Away"
There are several Omega-3 fatty acids. The two most commonly taken are DHA(docosahexaenoic acid) and EPA(eicosopentaenoic acid).
DHA is a polyunsaturated fatty acid that is found in tissues of marine animals. It is converted to EPA in humans. DHA competes with arachidonic acid for inclusion in cyclooxygenase and lipoxygenase pathways (substances responsible for inflammation). This competition may be responsible for its anti-inflammatory effect.
It reduces serum triglycerides (important in coronary artery disease). Increases fasting insulin and glucose concentrations(important for diabetes). It increases HDL (good cholesterol) by about 12 percent. It has an additive affect in reducing symptoms associated with schizophrenia and recurrent unipolar depressive disorder. The ethyl form of EPA is especially effective in depression (1gm twice a day). It slows weight loss in cachectic cancer patients. There is some evidence that suggests it to be helpful in prostate cancer.
It plays a key role in neural and synaptic membranes. These functions play a key role in learning and memory function. It is essential in healthy neurological development of infants. It is found in breast milk but not in standard infant formula. Supplementation is recommended for pregnant women beginning at week 15 (1.2gm-2gms/day).
It has been recommended for age-related macular degeneration, coronary disease, psoriasis(as an IV injection), hyperlipidemia, ADD, Alzheimer's. May also be beneficial in Multiple Sclerosis for its anti-inflammatory activity as well as its role in healthy neurological function.
The standard total Omega-3 fatty acid dose is 1800mg per day. It usually comes as a combination of EPA 350mg/DHA 200mg.
It is now well known that many of our diseases are in part a result of or are exacerbated by inflammation. Poor diets (high in saturated fatty acids and high glycemic index foods) as well as lack of adequate exercise play a significant role in the increase in inflammation in our bodies. Inflammation is a healthy response of the body to injury, but is problematic when it becomes chronic inflammation artificially produced by poor diet and a sedentary lifestyle. This inflammation affects our muscles, our vascular system and our neurological system, as well as our organs. Omega-3 fatty acids seem to block the inflammation pathway and help minimize subsequent damage. In addition to taking Omega-3's you should also minimize high glycemic foods in your diet. These include processed foods such as white sugar, white bread, pasta, etc. When we ingest high glycemic foods our pancreases release insulin and insulin is involved in a wide range of hormonal cascades which in turn cause inflammation.
DHA is a polyunsaturated fatty acid that is found in tissues of marine animals. It is converted to EPA in humans. DHA competes with arachidonic acid for inclusion in cyclooxygenase and lipoxygenase pathways (substances responsible for inflammation). This competition may be responsible for its anti-inflammatory effect.
It reduces serum triglycerides (important in coronary artery disease). Increases fasting insulin and glucose concentrations(important for diabetes). It increases HDL (good cholesterol) by about 12 percent. It has an additive affect in reducing symptoms associated with schizophrenia and recurrent unipolar depressive disorder. The ethyl form of EPA is especially effective in depression (1gm twice a day). It slows weight loss in cachectic cancer patients. There is some evidence that suggests it to be helpful in prostate cancer.
It plays a key role in neural and synaptic membranes. These functions play a key role in learning and memory function. It is essential in healthy neurological development of infants. It is found in breast milk but not in standard infant formula. Supplementation is recommended for pregnant women beginning at week 15 (1.2gm-2gms/day).
It has been recommended for age-related macular degeneration, coronary disease, psoriasis(as an IV injection), hyperlipidemia, ADD, Alzheimer's. May also be beneficial in Multiple Sclerosis for its anti-inflammatory activity as well as its role in healthy neurological function.
The standard total Omega-3 fatty acid dose is 1800mg per day. It usually comes as a combination of EPA 350mg/DHA 200mg.
It is now well known that many of our diseases are in part a result of or are exacerbated by inflammation. Poor diets (high in saturated fatty acids and high glycemic index foods) as well as lack of adequate exercise play a significant role in the increase in inflammation in our bodies. Inflammation is a healthy response of the body to injury, but is problematic when it becomes chronic inflammation artificially produced by poor diet and a sedentary lifestyle. This inflammation affects our muscles, our vascular system and our neurological system, as well as our organs. Omega-3 fatty acids seem to block the inflammation pathway and help minimize subsequent damage. In addition to taking Omega-3's you should also minimize high glycemic foods in your diet. These include processed foods such as white sugar, white bread, pasta, etc. When we ingest high glycemic foods our pancreases release insulin and insulin is involved in a wide range of hormonal cascades which in turn cause inflammation.
Folic Acid as Cinderella and Homocysteine as the Evil Stepmother
Folic Acid as Cinderella and Homocysteine as the Evil Stepmother
By: Cristina Berard, RPh, MEd
Folic acid or folate as it is also called, is found in green leafy vegetables. Folate from vegetables is about 40-50% less bioavailable than synthetic folic acid, which is almost 100% bioavailable. After it is absorbed by the body it is converted into tetrahydrofolate. Tetrahydrofolate based coenzymes play a major role in intracellular(within the cell) metabolism. Folic acid reduces errors to DNA and prevents replication errors. Folate deficiency disturbs the cycling of the cells and induces and increases the rate ofcell aptopsis (cell death). It is involved in the metabolism of homocysteine (high levels cause inflammation). Low levels of Folate are associated with an increase plasma homocysteine levels. High levels of homocysteine (hyperhomocysteinemia) is a risk factor for coronary, cerebral, and peripheral atherosclerosis; recurrent thromboembolism; deep vein thrombosis; myocardial infarction; and ischemic stroke.
Why are high homocysteine plasma levels a risk factor for certain diseases? The mechanism of action isn't fully understood, but it might include vascular endothelial cell damage(deterioration of the blood vessels), impaired endothelium dependent vasodilation (blood vessels don't dilate properly) due to reduced nitric oxide activity, arterial stiffening due to increase in oxidation(arteries become stiff) and arterial deposition of low density lipoproteins (LDL cholesterol deposits in the lining of the artery), increase of platelet adhessiveness (blood thickens becomes less viscous), and activation of the clotting cascade (increase in clots formed in the vessels).
All vitamins are essential and play important roles in metabolic pathways. Folic acid is an especially important vitamin. The following description of it's role may at times be a bit technical, but it is important in helping you to understand just how imperative it is to ensure that you are not deficient in folic acid or in any steps along the way.
Homocysteine is metabolized via two pathways. One is called "remethylation" the other "transsulfuration".
remethylated
Homocystein-----------------------> methionine
This reaction is facilitated by folate and Vitamin B12 (cofactors). Without these two cofactors, this processes would not take place and homocystein would remain in tact, thus increase homocystein levels in blood stream. There is another factor that can impede this process. Some people homozygous fo the mutations of the gene MTHFR(5,10 methyltetrahydrofolate reductase). This is an enzyme involved in the conversion of homocysteine to methionine. When you are homozygous for this gene most often you need to take higher doses of folate, usually 1mg per day.
Transsulfuration usually occurs after an individual ingests a meal high in animal protein (a methionine load).
via pyrodoxine(vit B6)
Homocystein-------------------------->cystathionine------------------------------->cysteine
Deficiency of pyrodoxine impairs the pathway raising homocysteine levels as well. In addition to folic acid, vitamin B12 and B6 are important for successful conversion of homocysteine.
What does all of this mean and why is it important to health? Well plays an important role in pregnancy and the healthy development of the fetus. Low levels are associated with neural tube defects in the fetus.
Low levels might play a role in Alzeihmers Disease. It seems to be associated with atrophy of the cerebral cortex.
Homocysteine is thought to be neurotoxic, causing DNA damage and cell apoptosis which is associated with functional and mental deterioration in the elderly.
Folic acid deficiency is common in people with depression. Low levels have been linked to poor response to antidepressant treatment.
Folic acid is required for the conversion of homocysteine------->SAMe. SAMe in turn is associated with an increase in serotonin turnover, increase in dopamine, and norepinephrine levels. All of these play a role in mood.
When you go to the pharmacy, you will find that there are individual B vitamins and then there are products that provide a combination of all B vitamins. The previous pathways might have given you a clue as to why these B vitamin complexes are so popular. Various B vitamins played a key role in these homocysteine conversion pathways. Where folic acid is the work horse, the other B vitamins are its helpers. Just like Cinderella was the hard worker of the family she couldn't have made it to the ball without her little helpers. By working together they were able to stop the evil stepmother (homocysteine) from getting her way.
Folic acid supplementation is helpful in treating and or preventing the following conditions: End-stage renal disease, hyperhomocysteinemia (11 micromoles/L or higher), methotrexate toxicity, neural tube defects, breast cancer, colorectal cancer, depression, Alzheirmers, risk of cervical cancer, cognitive function, infertility, and restless leg syndrome.
Typical doses are: 250mcg-1000mcg/Day
Severe disorders and under medical supervision(1000-5000mcg/Day)
By: Cristina Berard, RPh, MEd
Folic acid or folate as it is also called, is found in green leafy vegetables. Folate from vegetables is about 40-50% less bioavailable than synthetic folic acid, which is almost 100% bioavailable. After it is absorbed by the body it is converted into tetrahydrofolate. Tetrahydrofolate based coenzymes play a major role in intracellular(within the cell) metabolism. Folic acid reduces errors to DNA and prevents replication errors. Folate deficiency disturbs the cycling of the cells and induces and increases the rate ofcell aptopsis (cell death). It is involved in the metabolism of homocysteine (high levels cause inflammation). Low levels of Folate are associated with an increase plasma homocysteine levels. High levels of homocysteine (hyperhomocysteinemia) is a risk factor for coronary, cerebral, and peripheral atherosclerosis; recurrent thromboembolism; deep vein thrombosis; myocardial infarction; and ischemic stroke.
Why are high homocysteine plasma levels a risk factor for certain diseases? The mechanism of action isn't fully understood, but it might include vascular endothelial cell damage(deterioration of the blood vessels), impaired endothelium dependent vasodilation (blood vessels don't dilate properly) due to reduced nitric oxide activity, arterial stiffening due to increase in oxidation(arteries become stiff) and arterial deposition of low density lipoproteins (LDL cholesterol deposits in the lining of the artery), increase of platelet adhessiveness (blood thickens becomes less viscous), and activation of the clotting cascade (increase in clots formed in the vessels).
All vitamins are essential and play important roles in metabolic pathways. Folic acid is an especially important vitamin. The following description of it's role may at times be a bit technical, but it is important in helping you to understand just how imperative it is to ensure that you are not deficient in folic acid or in any steps along the way.
Homocysteine is metabolized via two pathways. One is called "remethylation" the other "transsulfuration".
remethylated
Homocystein-----------------------> methionine
This reaction is facilitated by folate and Vitamin B12 (cofactors). Without these two cofactors, this processes would not take place and homocystein would remain in tact, thus increase homocystein levels in blood stream. There is another factor that can impede this process. Some people homozygous fo the mutations of the gene MTHFR(5,10 methyltetrahydrofolate reductase). This is an enzyme involved in the conversion of homocysteine to methionine. When you are homozygous for this gene most often you need to take higher doses of folate, usually 1mg per day.
Transsulfuration usually occurs after an individual ingests a meal high in animal protein (a methionine load).
via pyrodoxine(vit B6)
Homocystein-------------------------->cystathionine------------------------------->cysteine
Deficiency of pyrodoxine impairs the pathway raising homocysteine levels as well. In addition to folic acid, vitamin B12 and B6 are important for successful conversion of homocysteine.
What does all of this mean and why is it important to health? Well plays an important role in pregnancy and the healthy development of the fetus. Low levels are associated with neural tube defects in the fetus.
Low levels might play a role in Alzeihmers Disease. It seems to be associated with atrophy of the cerebral cortex.
Homocysteine is thought to be neurotoxic, causing DNA damage and cell apoptosis which is associated with functional and mental deterioration in the elderly.
Folic acid deficiency is common in people with depression. Low levels have been linked to poor response to antidepressant treatment.
Folic acid is required for the conversion of homocysteine------->SAMe. SAMe in turn is associated with an increase in serotonin turnover, increase in dopamine, and norepinephrine levels. All of these play a role in mood.
When you go to the pharmacy, you will find that there are individual B vitamins and then there are products that provide a combination of all B vitamins. The previous pathways might have given you a clue as to why these B vitamin complexes are so popular. Various B vitamins played a key role in these homocysteine conversion pathways. Where folic acid is the work horse, the other B vitamins are its helpers. Just like Cinderella was the hard worker of the family she couldn't have made it to the ball without her little helpers. By working together they were able to stop the evil stepmother (homocysteine) from getting her way.
Folic acid supplementation is helpful in treating and or preventing the following conditions: End-stage renal disease, hyperhomocysteinemia (11 micromoles/L or higher), methotrexate toxicity, neural tube defects, breast cancer, colorectal cancer, depression, Alzheirmers, risk of cervical cancer, cognitive function, infertility, and restless leg syndrome.
Typical doses are: 250mcg-1000mcg/Day
Severe disorders and under medical supervision(1000-5000mcg/Day)
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