From a healthy heart to easing headaches: 14 ways Vitamin D can help you to feel better
About 50% of people here are thought to be deficient in vitamin D - which is vital for good wellbeing, growth and strong bones. Here, Shane Cochrane provides a comprehensive rundown as to why you might need the 'sunshine vitamin'.
1. You're planning on becoming a dad
Dr Cilia Mejia Lancheros and her colleagues at the School of Public Health, Physiotherapy and Sports Science, University College Dublin, have discovered that a father's pre-conception vitamin D intake is strongly linked to his child's weight and height at age five. Previously, only the mother's pre-conception vitamin D intake was believed to be important for a child's health. Other researchers have found that vitamin D might also be an important factor in male fertility, as it has been linked to sperm quality and testosterone levels.
2. You're planning on becoming a mum
A study led by Dr Quaker E Harmon of the National Institute of Environmental Health Sciences, North Carolina, found that women using contraceptives containing oestrogen have higher vitamin D levels than other women. But this tends to fall when a woman stops using the contraceptive. An earlier study of women undergoing IVF treatment, published in the Journal of Clinical Endocrinology & Metabolism, established that women who had "sufficient levels of vitamin D were more likely to produce high-quality embryos and more likely to become pregnant than women who were deficient in vitamin D". According to Dr Harmon: "Our findings indicate women may run the risk of developing vitamin D deficiencies just when they want to become pregnant. For women who are planning to stop using birth control, it is worth taking steps to ensure that vitamin D levels are adequate while trying to conceive and during pregnancy."
3. You have carpal tunnel syndrome
Research carried out at the Sakarya Training and Research Hospital in Turkey found that patients with carpal tunnel syndrome had significantly lower vitamin D levels in their blood. Even those with mild carpal tunnel syndrome were found to have significantly lower levels of the vitamin. This deficiency increased the intensity of the pain in the condition. However, the same study found that treating the deficiency could help alleviate the pain.
4. You suffer from headaches
Some headaches may be due to a vitamin D deficiency, according to researchers at the University of Eastern Finland. In a recent study involving 2,600 middle-aged Finnish men, researchers found that those with the lowest levels of vitamin D in their blood reported having headaches at least once a week. The headaches were more frequent during the non-summer months. The researchers, who are not entirely sure of the mechanism behind the results, concluded that more studies are needed to investigate vitamin D's potential as a treatment for headaches.
5. You have asthma
Taking a vitamin D supplement alongside regular asthma medication has been found to reduce severe asthma attacks. The Cochrane organisation, which was created to analyse medical research findings, performed a systematic review of seven trials and found that the supplement reduced the risk of severe asthma attacks requiring hospital admission or a trip to A&E from 6% to 3%. Vitamin D also reduced the number of asthma attacks that required treatment with steroids. However, the reviewers did note that the supplement did not improve lung function or day-to-day asthma symptoms and that more research is needed to determine if a vitamin D supplement will help all asthma sufferers or just those with a vitamin D deficiency.
6. You work indoors
Working indoors greatly increases your risk of vitamin D deficiency, according to the results of a review of 71 studies by the University of Alberta. The review, which included data on 53,425 people, found that 76% of indoor workers had a vitamin D deficiency.
"Workplace wellness programmes could include education about the importance of adequate vitamin D levels," said Sebastian Straube, one of the authors of the study. "This could prevent adverse health outcomes linked to vitamin D deficiency, such as metabolic disorders, psychiatric and cardiovascular disorders, and cancer."
7. You want to look after your heart
After tracking the health of 10,000 Americans for 20 years, researchers at Johns Hopkins University concluded that exercise combined with good vitamin D levels could reduce the risk of heart attacks and strokes. They found that those who got adequate exercise and had good vitamin D levels had a 23% less risk of having an "adverse cardiovascular event" than those who took little exercise and were vitamin D deficient.
8. You're menopausal
Lower urinary tract symptoms - such as urinary incontinence and excessive urination at night - are a very common feature of life after the menopause for many women. However, researchers at the University Hospital of North Norway and University College Cork found that women receiving a high dose of a vitamin D supplement twice a week experienced a reduction in their lower urinary tract symptoms. According to the researchers, vitamin D levels may affect pelvic floor strength and the detrusor muscle, which is found in the wall of the bladder.
9. You're getting older
Each year, about 30% of over 65s experience a fall. About 20% of those who fall will require medical attention. And some of those will experience physical and psychological complications and require hospitalisation or time in a nursing home.
Poor balance, poor muscle strength, cognitive impairment and certain medications have all been identified as increasing the risk of falls. But low levels of vitamin D have also been linked with falls in older adults.
A study by University of Nebraska Medical Center and Creighton University Medical School found that increasing vitamin D intake could decrease falls. However, this study's findings weren't entirely straightforward. According to the researchers, while a medium dose of vitamin D was found to decrease falls, a high dose of the vitamin actually increased them.
10. You have a higher risk of depression
At Oregon State University, a study that monitored the health of 185 female students found a relationship between low levels of vitamin D and depression. Many of the women who took part in the study were found to have low vitamin D levels. And one-third of the women experienced "clinically significant" depressive symptoms during the course of the study. "Depression has multiple, powerful causes and if vitamin D is part of the picture, it is just a small part," said David Kerr, the study's lead author. "But given how many people are affected by depression, any little inroad we can find could have an important impact on public health." But it's not just young women who are at risk. A 2017 study by the University of New South Wales found that anyone with a vitamin D deficiency is at an increased risk of depression.
11. You're a bit sporty
A study involving college football players in the USA found that those with low vitamin D levels were at greater risk of muscle injuries. Surprisingly, more than half of these athletes were found to have low vitamin D levels. "Awareness of the potential for vitamin D inadequacy could lead to early recognition of the problem in certain athletes. This could allow for supplementation to bring levels up to normal and potentially prevent future injury," said Scott Rodeo, who led the study. Even though the study focussed on elite athletes, Rodeo believes that "it's probably a good idea for anyone engaging in athletic activities to give some thought to vitamin D. Indeed, adequate levels of vitamin D are important to maintain good muscle and bone health in people of all ages."
12. You get a lot of colds
A study by Queen Mary University of London found evidence that vitamin D protects against acute respiratory infections. The study reviewed evidence from 25 separate clinical trials, and included data from 11,000 people in 14 countries. According to the study's lead author, Professor Adrian Martineau, their findings support the argument for the fortification of foods. "Vitamin D fortification of foods provides a steady, low-level intake of vitamin D that has virtually eliminated profound vitamin D deficiency in several countries. By demonstrating this new benefit of vitamin D, our study strengthens the case for introducing food fortification to improve vitamin D levels in countries such as the UK where profound vitamin D deficiency is common."
13. You want to stay mentally sharp
In 2015, researchers at the UC Davis Alzheimer's Disease Centre and Rutgers University examined the link between vitamin D deficiency and cognitive decline in older adults. Over five years, the researchers followed the progress of 400 men and women. Some of the men and women had dementia, some had mild cognitive impairment and some were "cognitively normal". The researchers found that, cognitively, those with a vitamin D deficiency declined up to three times faster than those with adequate vitamin D levels. "This work, and that of others, suggests that there is enough evidence to recommend that people in their 60s and older discuss taking a daily vitamin supplement with their physicians," said Professor Joshua Miller of Rutgers University. "Even if doing so proves not to be effective, there's still very low health risk in doing it."
14. You have an inflammatory bowel disease
In Ireland, approximately 15,000 people suffer from an inflammatory bowel disease, such as Crohn's disease or ulcerative colitis. A five-year study by the University of Pittsburgh found that 30pc of the people with inflammatory bowel disease they looked at had low vitamin D levels. And those with low vitamin D suffered more with the condition, required more frequent courses of steroids, needed greater pain relief and were more likely to need surgery.