Vitamin D deficiency is a very important health issue that affects the vast majority of people in the UK, and the main reason for the deficiency is lack of adequate sun exposure. Vitamin D is primarily manufactured in the skin where it transforms cholesterol into the vitamin on contact with sunshine.
The vitamin D status of the UK has been assessed since 2001, as a component of The National Diet and Nutrition Survey, and according to them :
• 90% of the general population have below optimal levels of vitamin D
• 75% of young adults, the elderly and British Asian children are deficient.
• 20-60% of the general population are deficient
• 20-40% of young men and women (19-24years), women over 85 years, residents of care homes over 65 years, and children of British Asians are severely deficient
• 5-20% of the population are severely deficient
These are frightening statistics!
So why are we so deficient?
The simple answer is that we aren’t getting as much sun as we used to. Our ancestors, millions of years ago, lived naked in the sun, living and working outside. Over the years we have put clothes on, started working indoors, travelling in cars and living in buildings that block the sun! More recently the scares of developing cancer from the sun have minimised the exposure even more and we now smother our children and ourselves in high factor sunscreen that blocks vitamin D!
Whilst there are some foods that naturally contain Vitamin D or are fortified with it, dietary sources alone are insufficient to satisfy human requirements. Salmon, mackerel, sardines, herring, trout, and fresh tuna (not tinned) are particularly rich sources with wild salmon providing 500-1000 IU of vitamin D per 100g and farmed salmon providing 100-250 IU per 100g serving. So an adult would need to eat 2-4 servings of wild salmon a day to maintain the daily vitamin D requirements.
Why do we need Vitamin D3?
Well it contributes to numerous functions in the body.
High vitamin D levels can lower the rate of ALL cancers by 77%
People with the highest levels of vitamin D have a 43% lower rate of heart disease
Men with the highest levels of vitamin D have less skin cancer
Women with high vitamin D levels have 20% less bone loss and fractures
People with high vitamin D levels have 20% lower rates of gum disease
People with the most vitamin D have a 55% lower rate of diabetes
And vitamin D is a mood enhancer, too.
We know that Vitamin D is vital for skeletal health and rickets, the classic vitamin D deficiency disorder is resurging in the UK, but there is more and more evidence to show that a vitamin D deficiency may have many other important health consequences.
Vitamin D is crucial for the absorption and metabolism of calcium and phosphorous, which have various functions, especially the maintenance of healthy bones.
It has been found that those children who developed rickets in the first year of their life had 3 times the risk of developing type1 diabetes, compared with those who did not develop rickets. In a recent study by researchers in Finland, it was found that children who took the recommended amount of vitamin D, 2000 IU a day in their first year of life, lowered the incidence of diabetes by 80% .
Vitamin D is required for the maintenance of normal muscle function.
Vit D is an immune system regulator and is know to help fight disorders such as the common cold.
Vit D helps to increase the production of Serotonin, a neurotransmitter that in low levels in the body is associated with mood disorders such as depression and seasonal affective disorder (SAD).
Vitamin D may play a key role in helping the brain to keep working well in later life.
It can reduce the severity and frequency of asthma symptoms and the likelihood of hospitalisation, researchers from Harvard Medical School found, after monitoring 616 children in Costa Rica.
Various studies have shown that those people with adequate levels of Vitamin D have a lower risk of developing cancer. Vitamin D deficiency was found to be prevalent in cancer patients regardless of nutritional status, in a study carried out by Cancer Treatment Centers of America.
So how much vitamin D do we need?
The current recommendation is 200 IU but if you consider that the skin will naturally produce 10,000 IU in response to 20-30 minutes of summer sun exposure, you can easily see that the recommendation is very low.
The correct level of vitamin D supplementation is the one which brings the blood level of vitamin D into an optimal range which may be different for each individual. Some medical literature suggests 5000 IU is more realistic to promote optimal levels.
Supplements should contain vitamin D in the form of D3 (cholecalciferol) because this is the form that is naturally produced by the skin upon exposure to sunlight.