Vitamin B12

Vitamin B12 is critical nutrients that help body make healthy red blood cells. Vitamin B₁₂, also known as cobalamin is a micronutrient that is synthesized only by microorganisms. In chronic lack of Vitamin B12 the body can't make needed amount of red blood cells. The major signs of vitamin B₁₂ deficiency are megaloblastic anemia and neuropathy. Vitamin B12 deficiency is common in people of all ages who consume a low intake of animal-source foods, including populations in developing countries. Strict vegetarians /vegans have a greater risk of developing vitamin B₁₂ deficiency relative to nonvegetarians. 

Animal products like meat, poultry, seafood and dairy foods like milk, eggs, yogurt, and cheese are the best sources of vitamin B12. The vegans are at risk for B12 deficiency since most vitamin B12 in the diet comes from animal products. Honey, vegetables, and fruits are not really sources of vitamin B12, which is why vegan diet does not contain enough vitamin B12. Therefore, vegan pregnant and nursing mothers or even strict vegetarians are recommended food fortified with B12 or B12 supplement. 

Fatigue is the most common symptom for individuals with low levels of vitamin B12. A sign of B12 deficiency includes weight loss, constipation or diarrhea, nausea and vomiting, abdominal bloating and gas, numbness or tingling in the hands and feet, loss of balance, and a sore, red tongue. Most people with vitamin B12 deficiencies have a mild problem. However it can at times be serious when there is an extremely low level of Vitamin B12 in the body. Some of the serious consequences due to vitamin B12 deficiency are mental problems, confused thinking, memory loss, and dementia. Low levels of B12 can also cause nerve damage and weaken bones. Vitamin B12 deficiencies occur when body does not get the right nutrients from our dietary intake. Sometimes B12 deficiency is caused by conditions other than diet; such as body inability to absorb B12 properly or when there is problem of the digestive system. Elderly individuals have more problems with malabsorption of B12 from food and malnutrition therefore, vitamin B12 deficiency is prevalent among the elderly. Crohn's and celiac disease, weight loss surgery, chronic alcoholism all interferes with the body’s ability to absorb enough of the nutrients needed. Drugs like antibiotics, antacids, diabetes and seizure medications can interfere with the body's ability to break down vitamin B12 from food.

The Institute of Medicine recommends that adults over age 14 years need at least 2.4 micrograms of B12 a day while pregnant or breastfeeding women need slightly more. However, daily body loss of the vitamin is estimated to be between 2 and 5 µg/day. It has been reported that a daily vitamin B₁₂ intake of 6 µg appears to be sufficient to maintain a steady-state concentration of plasma vitamin B₁₂ and vitamin B₁₂ related metabolic markers. A blood test at doctor’s office will help confirm vitamin B12 deficiency.

Vitamin B12 deficiency can be corrected by making adjustments in diet by taking B12-fortified foods or by taking a supplement. We can get plenty of Vitamin B12 by eating a well-balanced diet. Some people easily boost their low levels of B12 by simply changing their diet, eating more animal products, as vitamin B12 in our diets comes from animal products such as, seafood, yogurt, cheese, and eggs. However, in more serious cases of Vitamin B12 deficiency doctor’s care is needed. Many people may have a severe deficiency or have an underlying health condition that causes B12 to drop. Vitamin B12 deficiency is treated in several ways. If the symptoms are mild or moderate, an oral B12 supplement is started, which is taken once a day or a weekly vitamin B12 nasal spray is used. Serious B12 deficiencies may require B12 injections, which are administered occasionally.

Vitamin D: The Sunshine Vitamin

Vitamin D was first discovered at the beginning of the 20th century, as a missing nutrient in children causing severe bone demineralization, a disease called rickets. Vitamin D plays a pivotal role in metabolizing calcium for healthy bones. Insufficient vitamin D makes bones thin and brittle causing rickets in children and osteomalacia in adults. Vitamin D has multiple non-skeletal actions besides its major role in calcium homeostasis and bone metabolism.

The term "vitamin D" refers to two different forms; (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants and vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight. Vitamin D, as either D₃ or D₂, does not have significant biological activity it must be metabolized within the body to the hormonally-active form known as 1, 25-dihydroxycholecalciferol.

The major sources of vitamin D are our diet, supplementation and sun exposure. The good food sources of Vitamin D are fish liver oils, fatty fish, fortified milk products, fortified cereals. However, vitamin D is found in very few foods naturally (e.g. fish, eggs and cod liver oil); while foods such as milk, orange juice, yogurts and some breakfast foods are fortified with Vitamin D. Foods may be fortified with vitamin D2 or D3. The fortification level is aimed at about 400 IU per day.

Vitamin D is formed naturally as a result of sunlight exposure; as little as 10 minutes of sun exposure is thought to be enough to prevent vitamin D deficiencies. Lack of proper sun exposure or inadequate Vitamin D3 supplement increases body’s odds to vitamin D deficiency or insufficiency.

The Recommended Daily Amount (RDA) or Adequate of Vitamin D for adults’ age 18-50 years, pregnant and breastfeeding women is 5 micrograms/day. The RDA for adults’ age 51-70 years is 10 micrograms/day, while for adults over age 70 years RDA is 15 micrograms/day. Upper limit or the highest amount of Vitamin D taken without risk is said to be 50 micrograms/day. (The recommended daily intake of vitamin D is 200 international units (IU) for people up to 50 years old and 400 IU for people 51 - 70 years old and 600 IU for people over 70 years old.)

The Vitamin D blood levels should be around 50-80 ng/mL (125-200 nmol/L) for optimum health, these values are relevant to both children and adults. While, most doctors still consider a result of 30 ng/mL (75 nmol/L) to be sufficient; when it is not. Total serum 25(OH) D (25-hydroxyvitamin D) is the total amount of vitamin D in the blood, both vitamin D3 and vitamin D2. The only way to determine the body Vitamin D status is by testing Vitamin D blood levels. Vitamin D test tells us how much of the storage form of vitamin D, known as 25(OH) D is present in our blood serum. Vitamin D test can be obtained by asking the doctor for a 25-hydroxyvitamin D [5(OH) D] test. We need to be careful while ordering the right test a 25-hydroxyvitamin D test NOT a 1, 25-dihydroxyvitamin D test. We can also perform the test oneself by purchasing an in-home test kit.

Vitamin D deficiency is a highly prevalent condition. In spite of foods fortified with vitamin D and wide supplement intake, it is estimated that ~1 billion people have insufficient levels of vitamin D. According to Anthony Norman, an international expert on vitamin D, half the people in North America and Western Europe get insufficient amounts of vitamin D. Anthony Norman recommends a daily intake of 2000 international units for most adults. He says only eating vitamin D-rich foods are not adequate to solve the problem for most adults.

Lately, epidemiological data has shown prominent role of Vitamin D in autoimmune and cardiovascular disease as well as in cancer therefore interest in mechanisms of vitamin D action is growing persistently. Century later we are now aware of Vitamin D non-skeletal actions. Vitamin D has effect in target organ damage; Vitamin D receptor (VDR) is present in many tissues including immune cells and cardiovascular (CV) target organs.

Vitamin D ameliorates the target organ damage by enhancement of immune suppression/ modulation of immune responses; downregulates renin-angiotensin system and inhibits cardiac hypertrophy.

Several experimental data point towards beneficial effects of vitamin D in cardiovascular disease as it is said to have a novel role as a negative modulator of renin synthesis. One of the studies done by Wang et al., (2010) assessed whether vitamin D and calcium supplements reduced the risk for cardiovascular events in adults. They used data sources from clinical studies and trails from 1966 to July 2009. The findings showed consistent reductions in cardiovascular disease (CVD) mortality among adults who received vitamin D supplements in five prospective studies of patients receiving dialysis and one study involving a general population. However, study found no differences in incidence of CVD between calcium supplement recipients and nonrecipients in four prospective studies of initially healthy persons. Similarly, the results of secondary analyses in 8 randomized trials showed a slight but statistically nonsignificant reduction in CVD risk with vitamin D supplementation at moderate to high doses but not with calcium supplementation or a combination of vitamin D and calcium supplementation compared with placebo. The results suggest that vitamin D supplements at moderate to high doses may reduce CVD risk, whereas calcium supplements have minimal cardiovascular effects.

Likewise, several observational studies have suggested anti-inflammatory and immunosuppressive properties of vitamin D. Results have shown that vitamin D deficiency is associated with higher incidence of autoimmune diseases such as multiple sclerosis and type 1 diabetes mellitus. Evidences from a number of studies have reported substantial reductions in incidence of breast cancer, colon cancer and Type 1 diabetes in association with adequate intake of vitamin D. These positive effects were reported to have occurred within five years of initiation of adequate vitamin D intake.

Vitamin D has much potential health benefits, research so far suggest vitamin D provides protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases. However, more research needs to be done in some areas to make it even more comprehensible.

References:

Holick, M. F. (2007). Vitamin D deficiency. N Engl J Med, 357, 266–281.
Munger, K. L., Levin, L. I., Hollis, B.W., Howard, N. S., Ascherio, A. (2006). Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis. JAMA, 296, 2832–2838.

Wang, L., Manson, J. E., Song, Y., Sesso, H. D. ( 2010). Systematic review: Vitamin D and calcium supplementation in prevention of cardiovascular events. Ann Intern Med, 152, 315– 323.