Vitamin D is the ‘sunshine vitamin’ and is required for many body functions. It is required by the body to absorb calcium and both work together to build strong bones. Deficiency in essential vitamins and nutrients such as vitamin D are due to impaired absorption, dietary inadequacy, inability of the body to use the nutrients efficiently, increased excretion or increased requirement.
Vitamin D Deficiency
When people do not get sufficient vitamin D from diet, they can take vitamin D supplements and get sufficient exposure to light, which is also very critical. The following are some groups who can suffer from a deficiency and require supplements.
Breastfed babies: Babies whose only nourishment is mother’s milk can be at risk of a vitamin D deficiency especially if the levels in the mother are also low. Mothers who take high vitamin D doses will have sufficient vitamin D in breast milk. Lower income group women are most at risk of suffering from a deficiency. Some pediatricians recommend giving babies 400 IU vitamin D every day since it is usually advised that they be kept out of direct sunlight and made to wear protective clothing.
Elderly people suffer from various nutrient deficiencies – including vitamin D – as their skin and body cannot manufacture vitamin D efficiently. Since they spend more time indoors, they do not get exposed to sun also.
Inadequate exposure to the sun is one reason for low levels of vitamin D. People who stay indoors for a major part of the day, those who wear long robes covering their entire body and those whose occupations reduce their sun exposure, are all susceptible to vitamin D deficiency. It has also been suggested that sunscreens that block the sun’s rays from penetrating the skin can also contribute to the deficiency although there is no real evidence of this.
Fat malabsorption is also a cause for vitamin D deficiency for this nutrient requires certain amount of fat deposits in the gut to enable the body to absorb it. People with cystic fibrosis, liver disease and Crohn’s disease are some of those who have fat malabsorption.
Dark-skinned individuals have greater levels of melanin pigmentation on their epidermis (outer layer of the skin). This naturally reduces the ability of the skin to produce vitamin D using sunlight.
Obese people and those who have undergone gastric weight-loss surgery are also at risk of a vitamin D deficiency. Obese people require greater intake of vitamin D to achieve optimal levels – 25(OH)D – than those of normal weight. The skin of obese people can synthesize vitamin D as efficiently as that of people with normal weight. However, since obese people have more subcutaneous fat, greater quantities of vitamin D gets locked into the fat than that which gets released for circulation. Obese people who undergo gastric bypass surgery also lose greater quantities of vitamin D as part of the small intestine is removed.
Diets: A person who is ovo-vegetarian, has a milk allergy, and is lactose intolerant or a vegan may not get sufficient vitamin D from diet.
Kidney and liver disease patients could suffer from deficiency of vitamin D since these organs are important for manufacturing the biologically active version of vitamin D.
Symptoms of vitamin D deficiency
- Muscle weakness
- Bone pain
- Rickets in children
- Osteomalacia in adults
- Certain forms of cancer
- Autoimmune diseases
- Cardiovascular diseases
- Cognitive impairment in senior citizens
Vitamin D toxicity
This occurs rarely and is caused by people taking large doses of vitamin D and not because of over exposure to the sun or any foods. Vitamin D toxicity is called hypervitaminosis D and it results in hypercalcemia or excess calcium in the blood. Vitamin D in excess of 50,000 IU taken every day for many months causes this toxicity. Safe RDA for adults is 600 IU per day.
Symptoms of toxicity
- Poor appetite
- Frequent urination weakness
- Kidney problems
Excess calcium in the blood due to excess vitamin D also leads to many medical problems like kidney stones and other kidney problems, confusion and disorientation, excessive deposit of calcium in the heart and lungs and poor appetite, nausea, vomiting, constipation and weight loss.
Treatment of toxicity involves immediate stoppage of excessive intake of vitamin D, medications like biphosphonates or corticosteroids and IV fluids.
Vitamin D supplements
The maximum amount of vitamin D that people get is from exposure to the sun. Clothing, sunscreen, cold weather, smog, clouds all prevent sun from reaching the skin. All these people and others with various health problems can take vitamin D supplements to maintain the adequate dosage. Vitamin D is usually included in multivitamin soft-gel capsules, tablets or liquids. Doctors may recommend that some people take vitamin D injections to overcome a deficiency.
Precautions : Issues with Vitamin D Excess
Taking excess of vitamin D causes many severe side effects some of which are”
- Extreme thirst
- Metallic taste in the mouth
- Weight loss
- Joint pain
- Poor appetite
- Sore eyes
- Itchy skin
- Frequent urination
- Muscle fatigue
Most scientists do not agree on what is the right amount of vitamin D that does not cause any side effects. The NIH has set maximum tolerable upper limit for people over 9 as 4000 IU.
People who suffer from heart and kidney diseases, sarcoidosis, tuberculosis and high phosphorous or calcium levels must be careful about the amount of vitamin D they take.
Try to get at least 10-15 minutes of sun exposure 3 times a week and your body will get enough vitamin D. The sun needs to penetrate the skin without any sunscreen especially in the legs, back, face or arms. If you are at risk of vitamin D deficiency, then find out the RDA for your needs and get it as supplements and vitamin D-rich foods. The RDA differs depending on age, gender and if you are pregnant or breastfeeding.