Vitamin D deficiency

During the 19th century, scientists found that the main constituents of different foods were carbohydrates, fats, proteins, minerals, and water. At the beginning of the 20th century, some physiologists conducted feeding experiments on mice with synthetic diets prepared by blending pure carbohydrates, fats, proteins, and mineral salts. They observed that animals would not grow on such synthetic diets and the result let scientists draw an inference that natural foods contain unknown substances which are essential for the life and growth of animals.

In 1912, these were called “accessory food factors” by Federick G. Hopkins and Casimir Funk coined the term “vitamine” from “vita” (life) and “amine”. The term vitamin originated from “vitamine”. Funk has been honored as the “Father of vitamins” on his 140th birthday. The most important lines of observations vis-à-vis investigations which facilitated scientists to focus their attention on the existence of vitamins in foods had been started as early as the sixteenth century when Capt. James Lencaster observed in 1591 that scurvy in mariners could be cured by lemon juice.

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In 1865, Trousseau cured rickets in children using cod liver oil. In 1882, a Japanese naval surgeon, Takaki, showed that beriberi could be prevented by replacing polished rice with wheat bread, vegetables, and milk. So far about 13 different vitamins have been isolated in pure state from natural foods. Almost all of them are essential for human beings. Those could be classified broadly into two classes: (i) Fat-soluble vitamins (A, D, E & K), and (ii) Water-soluble vitamins (C and the B-complex: B1, B2, B3, B5, B6, B7, B9 & B12), each playing vital role in bodily functions. The discovery and isolation of these vitamins occurred primarily during the first half of the 20th century, with the last one being vitamin B12 in 1948. Though vitamins are not themselves sources of energy or raw material for tissue building, they are crucial facilitators for energy-yielding reactions and metabolic and physiological processes throughout the body.

Without them, what needs to happen would not. We need very small quantities of vitamins, and these come almost exclusively from the foods we eat. But vitamin D is the exception. The few foods that contain it have very low quantities. Instead, unique among vitamins, vitamin D is synthesized from sunlight on our skin. The discovery of Vitamin D in 1922 was due to an effort to address dietary deficiency in children with rickets. Adolf Windaus received the Nobel Prize in Chemistry in 1928 for his work on the sterols and their connection with the vitamin D which is chemically known as cholecalciferol. It is also referred to as calciferol.

There are several forms of Vitamin D, but it mainly exists in two forms ~ vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). These two forms are almost similar in their structures and physiological activities. Therefore, the term “vitamin D” implies vitamin D2 or vitamin D3, or both. Vitamin D is a fat-soluble vitamin produced endogenously when ultraviolet ~ B (UV-B) rays present in sunlight strike the human skin and trigger its synthesis. A chemical compound called 7-dehydrocholesterol present in the human skin undergoes photochemical conversion into the vitamin D3 form of Vitamin D in the presence of UV-B radiations of sunrays. Vitamin D3 is converted into active forms in the liver and kidney. Vitamin D2 is not produced in the human body.

It is produced in plants and fungi. Several factors including climate, cloud, ozone layer thickness, aerosol, atmospheric pollution, clothing habits, long indoor stay, dark complexion (due to high concentration of pigment, melanin, in human skin), old age (due to the decreasing level of 7-dehydrocholesterol) retard the process of the photochemical reaction. As a result, formation of vitamin D decreases considerably. Vitamin D is often called the “sunshine vitamin”. Though vitamin D is called a vitamin, if its formation in human skin under the influence of sunlight and its physiological action is considered, technically, it is a hormone.

It deserves mention that vitamins are organic compounds which cannot be synthesized by the human body but are necessary for its proper functioning and health. These are obtained from dietary sources only. On the other hand, hormones are synthesized in the body from simple precursors and transported by the bloodstream to the targets for specific biological functions. Unlike many nutrients, vitamin D is not abundantly found in foods. Instead, our body produces it when we are exposed to the sun. The deficiency of vitamin D owes to the dependence on the sun coupled with modern lifestyles. This means many of us spend as much as 90 per cent of our time indoors.

And finding a sunny spot in the home or office won’t help, as UV rays can‘t penetrate most glass. There are other factors that can influence the amount our body makes, including obesity. Body fat will store much of the vitamin D made by the skin so that there is less available for the body to use. People of African, African-Caribbean, or South Asian origin find it harder to produce sufficient quantities because their darker skin contains more melanin, which acts as a natural sunscreen. Vitamin D is known to play a pivotal role in calcium and phosphorus metabolism, and is therefore essential for bone health.

Its deficiency is responsible for a classic deficiency disease called rickets in children, deformities of the skeleton, such as bowed legs, enlarged head, curvature of the spine, poor teeth and flabby legs. A disease known as Osteomalacia is characterized by extreme softness of bones, muscle pain and extreme weakness. Children suffering from rickets carry the risk of upper respiratory tract infections, including TB and influenza. Indeed, vitamin D plays a crucial role in managing overall health, from strengthening the bones to boosting immunity, keeping us active and supporting healthy cardiovascular function, muscular function, the endocrine system, as well as playing a vital role in cell-to-cell communication. The symptoms of vitamin D deficiency are often subtle. There are as many as 14 symptoms:

(1) fatigue and low energy level;

(2) frequent illness or infections;

(3) bone pain and muscle weakness;

(4) hair loss;

(5)anxiety and depression;

(6) slow wound healing;

(7) chronic back pain;

(8) weak or brittle bones;

(9) frequent headache;

(10) poor sleep quality;

(11) muscle cramps;

(12) increased risk of chronic diseases;

(13) weight loss;

(14) vision and eye problems. The World Health Organization recognized vitamin D as a global health issue. In a statement on vitamin D deficiencies, the World Medical Association stated it is a prominent health problem across the world and about one-third of the world population is estimated to have a serum concentration of vitamin D lower than required.

A report by the Indian Council for Research on International Economic Relations (ICRIER) has sounded the alarm over the worsening public health crisis in India: Vitamin D deficiency. Among children aged 0-10 years, 46 per cent suffered from rickets, while 80-90 per cent of the elderly were at risk of osteoporosis, raising the likelihood of fractures and long-term disability. According to the report entitled “Roadmap to Address Vitamin D Deficiency in India” the deficiency affects all age groups and professions, from children and outdoor workers to healthcare personnel. With one in five Indians affected, the think tank has described it as a “silent epidemic.”

According to The Endocrine Society, an International professional NGO, Vitamin D deficiency is said to be there if the 25-hydroxyvitamin (25 OH D) is less than 30 ng/ml (nanograms per one ml volume of blood) of blood. The recommended range is suggested as 40–60 ng/ml by the society. To maintain these levels, the recommended daily intake of Vitamin D should be between 400 and 1000 IU for infants; between 600 and 1000 IU for those between one and 18, and between 1500 to 2000 IU for adults.

The think tank has called for a national campaign, pricing reforms, food fortification, and better diagnostics to tackle the crisis. The deficiency was most severe in eastern India, where nearly 39 per cent of the population lacked sufficient levels. Urban lifestyle, high air pollution, indoor work culture, and societal norms discouraging sun-exposure were cited as key factors causing natural Vitamin D deficiency. Diets compounded the issue, with low consumption of Vitamin D-rich food like fish, eggs and dairy, especially among vegetarians and lactose intolerants. Actions suggested are:

(1) Reduction of GST on vitamin D supplements;

(2) Bringing both D2 (plant-based) and D3 (animal-based) formulations under price regulation;

(3) Expansion of food fortification beyond milk and oil to staples like wheat and rice;

(4) Integrating vitamin D testing into the existing health scheme like Anemia Mukt Bharat and improving midday meals under PM POSHAN by fortified items like eggs and milk. ICRIER called for a nationwide “Vitamin D Kuposhan Mukt Bharat” (vitamin D Malnutrition Free India) campaign using schools, media and community outreach to raise awareness, especially among children, pregnant women and the elderly.

Addressing vitamin D deficiency can reduce healthcare costs, boost productivity and support national development goals. Vitamin D is the custodian of human health, from birth to old age. It has a tremendous role in human life. During the concluding years of the 20th century and at the beginning of the 21st century, many applications of vitamin D have been discovered, which provide human beings with the remedies in challenging and previously incurable diseases. The presence of Vitamin D Receptors (VDR) in our brain, heart, pancreas, skin and immune system has been well documented, indicating that these organs require vitamin D for their proper functioning.

Research is in progress to find the new applications of vitamin D in some other health issues. However, the fascinating world of vitamin D has been revealed in the words of Dr. Andrew Well, the founder of Arizona Centre for Integrative Medicine, USA,: “Increasing the amount of vitamin D in the body can prevent or help treat a remarkable number of ailments from obesity to arthritis, from high blood pressure to back pain, from diabetes to muscle cramps, from upper respiratory tract infection to infectious diseases and from fibromyalgia to cancer of breast, colon, pancreas, prostate and ovaries. It can safeguard pregnancy, support ideal weight management, reduce abnormal cell growth and stave of infectious and chronic diseases. Who would not want these benefits?”

(The writer is a retired IAS officer)