Health

Part 2 - Rickets and Scurvy

Scurvy

Scurvy was known to the Greek physician Hippocrates and the need to eat fresh plant food or raw animal flesh to prevent scurvy was known from ancient times. People living in marginal and desert areas used the leaves of drought-resistant trees and in 1536, while exploring the St. Lawrence River, the French explorers Jacques Cartier, saved his men, who were dying of scurvy, with a local remedy made, by the indigenous people, by boiling the needles of the arbor vitae tree to make a tea. This was later found to contain 50 mg of vitamin C per 100 grams of leaves.

The first symptoms of scurvy are fatigue, loss of appetite, nausea and diarrhoea progressed to shortness of breath, fever, painful joints and muscles, bleeding gums, susceptibility to bruising, loss of teeth, poor wound healing, and finally fever, convulsions and eventual death.

Scurvy had long been a principal killer of sailors during the long sea voyages. In 1499, Vasco da Gama lost 116 of his crew of 170 and in 1520, Magellan lost 208 out of 230 men all mainly to scurvy.

John Woodall, the first surgeon to the British East India Company, recommended the preventive and curative use of lemon juice in his 1617 book, The Surgeon's Mate.

An early controlled experiment by a Royal Navy surgeon, James Lind, in 1747, demonstrated that scurvy was prevented by citrus fruit and, from 1796, lemon or lime juice was issued to all Royal Navy sailors. (Hence the slang term, 'Limey' used to describe an English man).

In 1769 Captain James Cook demonstrated the advantages of carrying "Sour krout" (pickled cabbage) on board, by taking his crews to the Hawaiian Islands without losing any of his men to scurvy.   For this, the British Admiralty awarded him a medal.

Vitamin C was discovered in 1912, isolated in 1928, and in 1933 was the first vitamin to be chemically produced. It is a water-soluble vitamin, important in forming collagen, a protein that gives structure to bones, cartilage, muscle, and blood vessels. Vitamin C also helps maintain capillaries, bones, and teeth and aids in the absorption of iron.

It is on the World Health Organization List of Essential Medicines, the most effective and safe medicines needed in a health system. Foods containing high levels of vitamin C include citrus fruits, kiwifruit, broccoli, brussels sprouts, raw bell peppers and strawberries. Albert Szent-Györgyi and Walter Norman Haworth were awarded the 1937 Nobel Prizes in Physiology and Medicine and Chemistry for their part in discovering vitamin C.

Rickets

As our hunter gatherer ancestors moved further north many were crippled or died of rickets, a disease causing deformed and weak bones. If they survived childhood, they often could barely walk because of severely bowed legs. In adults, rickets caused less obvious problems with fragile bones and cancers. People with dark skins tended to die before puberty so northerners tended to have paler skin.

In 1822 J. Śniadecki, noticed that children living in the inner city of Warsaw were plagued with rickets compared to those in rural areas who had more exposure to the sun. 

 In 1852 K.Huldschinsky reported that children exposed to a mercury arc lamp had dramatic improvement of their rickets. He also found that exposing one arm of a child to the lamp provided the same improvement to the other arm and concluded that something was being made in the skin which improved the health of all the child's bones. 

It was not until 1914 that American researchers Elmer McCollum and Marguerite Davis discovered vitamin A in cod liver oil and, in Britain, Edward Mellanby noticed that dogs fed cod liver oil did not develop rickets. McCollum found that another vitamin in cod liver oil was the active chemical which he called vitamin D.

In 1921 New York City, Doctors Hess and Unger demonstrated improvements after exposing children with rickets to sunlight on the roof of their hospital. They also realized that children with darker skin were at higher risk for rickets and needed longer exposure to sunlight to both treat and prevent rickets.

In 1923, American biochemist Harry Steenbock discovered that rodents were cured of rickets after being fed irradiated food. This irradiation technique was made mandatory for some foodstuffs, especially milk, and after 1935 rickets was essentially eliminated in the USA.

Vitamin D, assists in the absorption of calcium and phosphorus into bones and helps to conserve minerals in the kidney. The main source of Vitamin D historically was from human skin exposed to ultraviolet (UVB) rays from bright sunshine. The main food sources are from eggs, liver and small fish, although some researchers doubt that most people today can get an adequate amount of vitamin D from sunlight or food and recommending vitamin D supplements for most people, especially people over 50 years of age.

The American Academy of Pediatrics recommends breastfeeding babies be given vitamin D supplements particularly between the ages of 3 months to 18 months of age. 400 International Units (IU) of vitamin D per day under the age of 12 months and 600 IU per day for all older children. 

 For older adults 800 to 1000 IU per day of vitamin D is vital in maintaining bone strength and preventing osteoporotic fractures caused by falls. It is also important for muscle development and preservation.

Children and adults:- who drink little fortified milk, are not exposed to bright sunlight or who have dark skin, also need vitamin D supplements. Milk, some soy beverages and all infant formulas sold in the United States and Canada are vitamin D-fortified.

Vitamin D is made by human skin exposed to ultraviolet radiation (UVB) from strong sunlight. This occurs around midday (about 10 am to 3 pm) between 37 degrees north or south of the equator. In winter North of Atlanta USA, the sun is never high enough in the sky for its UVB rays to penetrate the atmosphere, so it is nearly impossible to produce vitamin D from sunlight. This is why dark skinned people died out in northern areas leaving only white skinned people who could make vitamin D in weak sunlight. Unfortunately, excessive UVB radiation can burn the skin and increase the risk of skin cancer so it is wise to limit exposure to about half the time needed to cause sunburn. People with darker skin, which can provide up to ten times more protection from sunburn, must get up to ten times more exposure to produce the same amount of vitamin D as people with lighter skin colour.

People who decide to expose unprotected skin to bright sun light to obtain more vitamin D should: Protect the their face and top of their ears because those are the most exposed to sunburn. For pale skin, Allow 10 to 15 minutes or so of unprotected sun exposure to arms, legs, abdomen and back. After that, follow up with good sun protection, like a 30-SPF or higher sunblock. For dark skin, up to two hours of exposure may be needed before applying sun screen. Choose a time between 10 am and 3 pm. If your shadow is longer than your body height, UVB radiation can not penetrate the atmosphere to make vitamin D. Check the weather news which usually reports the relative UVB rating on a scale from 0 to 10 the lower the number, the more time needed to make vitamin D but make sure a low number is not because of variable cloud cover.