Vitamin D is a vitamin usually fat soluble and is unique in relation to other vitamins as a result body could produce it in adequate amounts with the help of sun. Researchers consider that some cells produce Vitamin D as it circulates and affect tissue throughout body and might be classified as hormone than vitamin. The ability of the body to make Vitamin D relies on sunlight exposure and everybody does not receive adequate exposure. Moreover, also direct exposure to sunlight is not advised as it increases the chances of skin cancer. Due to this reason, vitamin D is regarded as vitamin. Vitamin D is also called sunshine vitamin which is formed by the body when exposed to sunlight and could also be obtained through supplements and food.
What Foods Provide Vitamin D?
There are two possible ways of supplying the body with vitamin D: through diet and exposure to the sunlight. The richest sources of vitamin D in human diet are vitamin D-fortified milk and milk products, salmon, tuna, herring, margarine (vitamin D fortified), and vitamin D-fortified cereals. Vitamin D in foods appears fairly stable in various cooking and storing procedures. Vitamin is available in nutrition supplements in the form of cholecalciferol. International Units are used to express vitamin D levels on packaging by 1 microgram is equal to 40 IU of vitamin D. Thus 10 micrograms would be equal to 400 IU which is commonly used in supplements and provides 100 percent of the Daily Value (DV).
|Food name||Weight (g)||Vitamin D (µg)||DV%|
How Much Vitamin D Do We Need?
The recommended daily intake for adults 50 years of age and younger as well as pregnant women is 5 micrograms (200 IU) of vitamin D daily. One microgram is the equivalent of 40 IU of vitamin D. For adults over the age of 50 and 70 the RDA increases to 10 and 15 micrograms (400 IU) daily.
How Much Sunlight Is Required to Make Vitamin D?
People having lighter skin color requires 10 minutes of sun exposure to make required amounts of vitamin D. This requires direct exposure of skin to sun during midday. However, sunscreen with SPF 8 or higher significantly reduces the process. Also the necessary exposure is increased for people with darker skin color and in a manner relative to the degree of darkness. This also means that a person will make less and less vitamin D as they tan longer or over several days, such as vacationing at the beach. This helps to protect people from potentially making too much vitamin D. Interestingly, the ability to make vitamin D appears to be stronger during youth and decreases as humans get older. For this reason, the need for vitamin D from food and or supplements increases as we get older (50+).
Can Too Much Vitamin D Be Consumed?
Of the vitamins, vitamin D has one of the lowest levels of intakes above recommendations that could give rise to side effects. Many of the manifestations appear to be related to vitamin D’s calcium absorption, which in turn results in too much calcium in the blood. Extended hypercalcemia (elevated blood calcium) affects muscle cell activity including heart and can promote vomiting, nausea, mental confusion, and lead to calcium deposition in various tissues throughout the body. While the Tolerable Upper Limit has been set at five times the AI for adults, more recent research suggests that the threshold for potential side effects of excessive intake could indeed be at double that level. Luckily, as exposure to sunlight increases the body’s ability to make vitamin D decreases. Additionally, when active vitamin D upsurges, kidney cells produce less and less of the converting enzyme needed to make more active vitamin D. These mechanisms attempt to decrease the potential for toxicity. That’s because we may be more sensitive to vitamin D toxicity than other vitamins when looking at the intake level associated with signs and symptoms.
Health Benefits of Vitamin D
Vitamin D is principally involved in calcium and bone metabolism with the addition of newer functions of vitamin D. Vitamin D functions include:
- Bone health
Vitamin D is essential for maintaining bone health. It has a vital role in regulating calcium and maintaining phosphorus levels in blood both of which are required for maintaining healthy bones. Vitamin D is essential for absorbing calcium in intestines and reclaims calcium which is either excreted through kidneys. The deficiency of Vitamin D found in children causes rickets which is a disease distinguished by severely bow-legged appearance due to bones softening. The deficiency of Vitamin D manifest as osteoporosis or osteomalacia. The muscular weakness and poor bone density is resulted due to osteomalacia which has become a common bone disease among older men and post-menopausal women.
- Lowers diabetes
Studies have shown negative relationship between blood concentration of Vitamin D found in body and risk of type 2 diabetes. The insufficient level of Vitamin D in type 2 diabetic patients effect insulin secretion and glucose tolerance negatively. Study has shown that intake of 2000 International Units per day of Vitamin D lowers the chances of type 2 diabetes by 88 percent.
- Infant health
Children having normal blood pressure were provided 2000 International Units per day lowers arterial wall stiffness significantly after 16 weeks in comparison to children who were provided 400 IU per day. Low content of Vitamin D is related with high chances and severity of atopic childhood diseases and allergic diseases such as atopic dermatitis, asthma and eczema. It promotes anti-inflammatory effects of glucocorticoids which makes it a supportive therapy for people having steroid resistant asthma.
- Pregnant health
Pregnant women with vitamin D deficiency are prone to high chances of developing preeclampsia and need cesarean section. Poor amount of Vitamin D is related with gestational diabetes mellitus and bacterial vaginosis in pregnant women. It is essential to note that during pregnancy high content of Vitamin D is related with increasing chances of food allergy in child during first two years of life.
- Prevent cancer
Vitamin D is essential to regulate cell growth and for cell-to cell communication. Studies have shown that calcitriol could lower progression of cancer by slowing development as well as growth of new blood vessels in cancerous tissue, lower cell proliferation & metastases and increasing cancer cell death. It manipulates more than 200 human genes which is impaired when do not have adequate vitamin D.
The deficiency of Vitamin D is related with increasing chances of cardiovascular disease, multiple sclerosis, hypertension, Alzheimer’s disease, autism, asthma severity, rheumatoid arthritis and swine flu
- Prevention from stroke and heart disease
Studies have shown that adequate amounts of Vitamin D lower the chances of stroke, heart disease and heart failure. Though some were based on controlled and randomized clinical trials, the basic aim of research is to analyze relationship between vitamin D and its association to bone strength and growth. The participants were women and older people over age 70. Furthermore, other studies review was based on the participants having end stage kidney failure. These factors suggest that research is required for determining real effect of Vitamin D on heart health and stroke risk.
- Prevent dementia and cognitive decline
Vitamin has a role in cognitive function as well as chances for dementia. Research shows that Vitamin D clears amyloid plaque which is the symptom of Alzheimer’s disease. But more studies are required for confirming cause & effect relationship between neurodegenerative disorder and adequate level of Vitamin D.
- Improves performance
Vitamin D has a vital role in muscle function and metabolism. The supplementation of Vitamin D helps to promote muscle strength, balance or physical performance.
- Helpful for depression
Vitamin D deficiency is related with 8 to 14% increase in depression. It increases suicide rates by 50%. Vitamin D supplements helps to lower depressive symptoms and promotes physical functioning in patients having depression. Some studies also showed that Vitamin D supplements neither improved nor worsened depressive symptoms. In elderly postmenopausal women, no effect of hormone therapy or Vitamin D was seen either individually or in combination of depression. Vitamin D promotes muscle strength by promoting atrophy of type II muscle fibers resulting in lower falls or hip fractures. Insufficient vitamin is related with increase in fat infiltration in muscles of healthy young women. It enhances athletic performance. Deficiency of this vitamin is correlated with increasing chances of injury or illness among athletes.
- Sound sleep
Vitamin D is found to be helpful for those having problem with sleep disorders. High content of this vitamin is related with better sleep. Low content of this vitamin is related with shorter sleep duration. Studies found out that supplements of Vitamin D improve quality of sleep. The deficiency of Vitamin D causes disturbed sleep patterns. Vitamin D deficiency is associated with production of abnormal glucose production. But further studies are required to prove the link between supplementation of Vitamin D and sleep quality.
Special Warnings and Precautions
- Pregnant and breastfeeding women should use it in proper doses according to the doctor’s recommendation.
- Vitamin D results high calcium levels in blood that affects the people with existing conditions such as sarcoidosis, atherosclerosis, histoplasmosis, tuberculosis, over active parathyroid gland and lymphoma.