Vitamin D
In the last post, we examined Vitamin A. In this post, we will look at yet another fat-soluble vitamin –Vitamin D.
There are two main forms of Vitamin D consisting:
- Vitamin D2 (ergocalciferol ) –mainly includes Vitamin D added in form of fortification or supplementation or form plat sources.
- Vitamin D3 (cholecalciferol) is produced in the skin of humans from 7-dehydrocholesterol and is majorly obtained from animal-based sources.
VitaminD2 and D3 are in inactive forms and they require to be activated in the liver and kidneys to 25-hydroxyvitamin D and (1,25 dihydroxyvitamin D)respectively.
In its active form, Vitamin D can perform its role of absorbing calcium and phosphorus.
Functions of Vitamin D
- Maintains bone health –Along with calcium, Vitamin D is important for strong bones. It aids in the absorption of calcium, and together they maintain the bone’s density.It also maintains proper phosphate levels , important for bones and teeth .
- For cell and muscle functions –Vitamin D is essential for cell division and specialization,and for muscle development and function.
- Maintains your immune system –You require Vitamin D to fight against invading pathogens such as bacteria.
Individuals At Risk Of Vitamin D Deficiency
Older adults -As you grow older, your skin’s capacity to synthesize vitamin D from sunlight exposure diminishes.
Individuals who rarely receive sunshine exposure- This could be because they often stay indoors and rarely go outside or perhaps because they usually cover up completely.
Vegans –Since most sources of Vitamin D are obtained from animal sources, this particular group is at increased risk of Vitamin D deficiency, especially if they also do not receive sunshine exposure.
Alcoholics-This could result if they have liver damage.
Individuals with conditions that affect the liver, and kidneys or impaired fat absorption, including celiac disease or Crohn’s disease. Remember, Vitamin D is a fat-soluble vitamin as such it requires fat for some absorption, if the absorption of fat is limited this also interferes with Vitamin D absorption.
Signs And Symptoms Of Vitamin D Deficiency
- Fatigue
- Bone pain
- Muscle weakness
- Poor appetite
- Depression
Additionally, ample amounts of vitamin D alongside proper nutrition, and physical activity- are crucial for the development and maintenance of bones.Vitamin D deficiency correlates with poor calcium absorption. As a result, calcium is extracted from the skeleton to utilize in the maintenance of serum calcium levels, leading to bone loss.
Inadequate Vitamin D levels and insufficient sunlight exposure are linked to an increased possibility of osteoporosis wherein bone density is reduced, thereby elevating the risk of fractures. Osteomalacia which is the softening of the bones, may also occur, as there is not enough vitamin D to uptake calcium, necessary for hardening the bones.
Children who do not obtain adequate amounts of Vitamin D, especially from sunlight are susceptible to rickets whereby they may have bowed legs.Infants should receive some sunlight exposure to prevent the likelihood of rickets. At least 15 – 20 minutes under the sun, though it should be at a time when it is not too hot.
Sources Of Vitamin D
The rich natural sources of vitamin D are:
- Saltwater fish e.g. herring ,mackerel, salmon, sardines.
- Fish liver oils
In insignificant amounts, it can be found in:
- Eggs
- Meat
- Liver
Plant sources such as mushrooms
Sunlight
RDA
Adults- both males and females -15 micrograms
Older adults (>70 years)) -20 micrograms
Vitamin D Toxicity
Intake of high amounts of vitamin D is unsafe. Notice, that Vitamin D toxicity mainly arises from supplementation rather than dietary intake. Toxicity signs and symptoms could manifest as;
- Nausea
- Vomiting
- Muscle weakness
- Low appetite
- Dehydration
- Confusion
In certain cases, exceedingly high vitamin D levels can result in, irregular heartbeat, kidney failure, and bone pain.
Nutrient Interactions With Vitamin D
- Calcium – Vitamin D aids in the absorption of calcium and together they protect against bone loss.
- Phosphorus –Vitamin D also aids in the absorption of phosphorus, also important for bone health and even teeth.
- Vitamin K- Vitamins D and K perform a vital role in calcium metabolism.
- Magnesium- Magnesium is necessary to activate vitamin D. Its deficiency results in the reduction of active vitamin D levels.
Drug Interactions With Vitamin D
- The bile acid sequestrants, for example, cholestyramine, may bind fat-soluble vitamins such as Vitamin D. Since Vitamin D metabolites are contained in bile, an increase in bile acid excretion, could imply a reduction of vitamin D body stores.
- Orlistat (a weight loss aid) may hinder Vitamin D absorption.
- Antimicrobials including rifampin and isoniazid also alter vitamin D status. Vitamin D is inhibited by isoniazid.
Vitamin D is important for you, especially in regard to bone health and muscle development. Apart from vitamin dietary sources, you can obtain it from sunlight. In exceeding amounts, however, it can present undesirable consequences, though this mainly occurs due to supplementation. Whereas it is found in limited natural food sources, combining the intake of these foods along with regular sunshine should ensure that you meet the required Vitamin D amounts.