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Vitamin D In The Spot Light!

Vitamin D is causing quite a stir in the news. A few years ago, Public Health England (PHE) recommended that to protect bone and muscle health, everyone needs vitamin D equivalent to an average daily intake of 10 micrograms. PHE also advised that in spring and summer, the majority of the population get enough vitamin D through sunlight on the skin and a healthy, balanced diet.
This advice is great, but the requirements for people who exercise regularly differ greatly from that of general population.

What is Vitamin D?

Vitamins are organic compounds (meaning they contain carbon) and can be characterised into water soluble vs fat solubleFat soluble vitamins are stored and sequestered into fat stores and therefore have a much longer bioavailability than water soluble vitamins. In contrast, water soluble vitamins are excreted out in urine if consumed in too large a quantity and are used by the body fairly quickly. Vitamin D ​is a fat soluble vitamin. 

Where does vitamin D come from?

Our bodies cannot produce vitamins except for one exception, vitamin D. The term vitamin D is, unfortunately, an imprecise term referring to one or more members of a group of steroid molecules. Vitamin D3, also known as cholecalciferol is generated in the skin of animals when light energy is absorbed by a precursor molecule 7-dehydrocholesterol. If someone has adequate exposure to sunlight, theorectically they do not require dietary supplementation.

How does my body synthesise Vitamin D?

Vitamin D, as either D3 or D2, does not have significant biological activity. Rather, it must be metabolised within the body to the hormonally-active form known as 1,25-dihydroxycholecalciferol by a 2 step process in the liver and then the kidney.


What does vitamin D do in the body?

Vitamin D is well known as a hormone involved in mineral metabolism and bone growth. Its most dramatic effect is to facilitate intestinal absorption of calcium, although it also stimulates absorption of phosphate and magnesium ions. In the absence of vitamin D, dietary calcium is not absorbed at all efficiently. Vitamin D stimulates the expression of a number of proteins involved in transporting calcium from the lumen of the intestine, across the epithelial cells and into blood. Not only does vitamin D assist in growth and maintenance of the bone, but it also aids in regulation of electrolyte metabolism, protein synthesis, gene synthesis and immune function

What happens if I exercise with low vitamin D levels?

Although there is not yet enough convincing evidence to support vitamin D as a direct performance enhancer, obtaining optimal Vitamin D levels can reduce the risk of debilitating stress responses in bone which may lead to stress fractures. In addition, because of its active role in muscle and protein synthesis, recovery and fatigue may also be improved, all impacting your performance. Newer studies are also suggesting that as immune function is boosted, active people are less likely to suffer from common colds (1).

What should I do to boost my vitamin D?

1. Sunlight exposure 
During the summer months, training or playing sport outdoors can have a massive impact in boosting your vitamin D stores. This can be further enhanced by maximizing skin exposure to sunlight e.g. by wearing shorts and t-shirts. Your body can’t make vitamin D if you are sitting indoors by a sunny window because ultraviolet B (UVB) rays (the ones your body needs to make vitamin D) can’t get through the glass. Sunscreen prevents sunburn by blocking UVB light. Theoretically, that means sunscreen use lowers vitamin D levels. But as a practical matter, very few people put on enough sunscreen to block all UVB light, plus the risks of unprotected sun exposure far outweighs any additional vitamin D you might receive!
Remember, the bioavailbility of your replenished vitamin D stores during the summer months will last for weeks to months and therefore stand you in good stead for the sun deprived winter.
2. Managing obesity 
A recent study funded by the British Heart Foundation has shown that for every unit increase in BMI (1kg/m2) was associated with a 1.15% reduction in the level of vitamin D in the blood (2). As we now know, Vitamin D is a fat soluble vitamin. This means the more vitamin we have ‘locked away’ in our fat stores, the lower the level circulating in our blood will be. This means we cannot effectively use the vitamin D in our body, the more fatty tissue we have. However, it also means, that we need adequate amounts of fat in our diet to absorb the Vitamin D in the first place. This again highlights the importance of a balanced healthy diet. For every unit increase in BMI, there is a 1.15% reduction in blood vitamin D levels.

3. Dietary intake
During autumn and winter, PHE recommends that everyone will need to rely on dietary sources of vitamin D, as sunlight is not enough. Vitamin D3 is also found in a small number of foods. Good food sources are:

  • Oily fish – such as salmon, sardines, herring and mackerel
  • Red meat
  • Liver
  • Egg yolks
  • Fortified foods such as most fat spreads and some breakfast cereals

The plant form of vitamin D is called vitamin D2 or ergosterol. In the UK, cows’ milk is generally not a good source of vitamin D because it isn’t fortified, as it is in some other countries. 

4. Supplementation
Another source of vitamin D is dietary supplements. Recent guidance from PHE has suggested that the Vitamin D recommendation from consuming foods naturally containing or fortified with vitamin D, people should consider taking a daily supplement containing 10 mcg (micrograms) of vitamin D in autumn and winter. Ethnic minority groups with dark skin, from African, Afro-Caribbean and South Asian backgrounds, may not get enough vitamin D from sunlight in the summer and therefore should consider taking a supplement all year round.

What does the mean for me?

There is currently no guidance for people who exercise regularly on vitamin D, but in my medical opinion, we should be counted as a high risk group. This means as well as taking the above measures including optimising sunlight exposure and diet, supplementation should be taken over the winter months. If you exercise and train all year round, you will be doing no harm by taking 10 mcg Vit D supplementation all year round. Bear in mind however that even this dose may not be enough for high level exercisers and it is always worth asking for your Vitamin D levels to be checked by your doctor.

What are normal values of vitamin D?

So you go to your doctor and get your vitamin D level checked. If they tell you it is normal. Great.

No, not great. It is always worth finding out the value of your Vitamin D level as what is considered ‘normal’ can vary greatly. There is consensus that levels below 25nmol/Lqualify as ‘deficient’, but beyond this there is currently no standard definition of ‘optimal’ Vitamin D levels. Some sources suggest that levels above 50nmol/L are ‘sufficient’, while 70–80nmol/L is ‘optimal (3). It is worth noting that normal ranges also differ depending on which laboratory you get your blood processed in. Most sporting bodies will advise their athletes keep their levels above 90-100 nmol/L .

In other words, don’t be afraid to challenge your doctor if you feel your vitamin D levels are not being taken seriously enough! Or if they tell you they are in the normal range but doesn’t take into account the fact you run 5 times a week. Optimising your Vitamin D intake is any easy way to improve your health and performance. 

1. Nutrients. 2013 Jun; 5(6): 1856–1868. 2013 May 28. doi: 10.3390/nu5061856. Vitamin D and the Athlete: Risks, Recommendations, and Benefits D, OganK, Pritchett.
2. Vimaleswaran KS, Berry DJ, Lu C, et al. Causal Relationship between Obesity and Vitamin D Status: Bi-Directional Mendelian Randomization Analysis of Multiple Cohorts. PLoS One Medicine. Published online February 5 2013
3. NICE. Vitamin D position statement. 2010.

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    Orla Mulligan
    Administration and Social Media Manager
    Administration, LBSM

    Orla Mulligan is the administration and social media manager for LBSM. She has a strong background in sport having herself played netball at an elite standard for the U21s Northern Ireland team in the European Championships as well as the U21s competition for Saracen Mavericks.

    She understands youth sport pathways having herself played and training in the netball Kent regional pathway. She has a keen interest in most sports and a good understanding of how injury and illness can impact on the mind and body, as well as rehabilitation pathways.

    She looks forward to speaking and assisting LBSM patients and gives her best support to them during their treatment pathway.

    A day in the life of Orla involves communicating with patients via phone and email, managing and organising clinics, operations and media management.

    Outside of work, Orla is a gym enthusiast, enjoys tennis and still finds the time for an occasional game of netball.

    Maddie Tait
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    Associate, LBSM
    Musculoskeletal and Sports Podiatrist

    Maddie treats and manages complex foot and ankle injuries in London and Surrey.

    She is particularly interested in helping her patients improve their quality of life and achieve their personal goals, working closely with Foot and Ankle Consultants, Sports Medicine Doctors and Physiotherapists.

    Maddie has a sporting background herself having previously represented England in Hockey. She understands the demands of elite sport and the importance of physical and mental health. In her spare time, Maddie continues to enjoy an active lifestyle by running, cycling and attending a Pilates class.

    Having graduated from University of Brighton with a MSc (hons) in Podiatry, Maddie focused her career in Podiatric Sports Injuries and Biomechanics. Previously she completed a BSc (hons) in Sport Science at Loughborough University.

    A day in the life of Maddie involves consulting patients in clinic, performing gait and biomechanical assessments, measuring and fitting orthotics and braces. She also regularly teaches and presents at sports medicine and podiatry conferences.

    Outside of work, Maddie still finds time to play hockey and enjoys running and skiing.

    Mr Prakash Saha
    Consultant Partner, LBSM
    Consultant in Vascular Surgery

    Mr Prakash Saha is a Consultant Vascular Surgeon at LBSM. He takes pride in providing the best possible results for his patients by using the most appropriate non-surgical and surgical methods based on clinical evidence, patient results and satisfaction.

    He treats fit and active people suffering with a range of cardiovascular issues, from painful leg swelling associated with exercise to venous insufficiency, post-thrombotic syndrome and leg ulcers. He also treats people with arterial system problems including poor circulation, compression syndromes and aneurysms. He carries out both endovascular and open aortic repair and has some of the best outcomes in the country.

    Mr Saha studied medicine at the United Medical & Dental Schools at Guy’s and St. Thomas’ Hospitals before completing his higher surgical training in London and the South East. During this time, he was awarded the prestigious NIHR Clinical Lectureship in Vascular Surgery at St. Thomas’ Hospital, giving him comprehensive training in open and endovascular techniques for treating arterial and venous disease. Prakash completed his aortic surgery training at the St. George’s Vascular Institute before carrying out a specialist fellowship at the Royal Prince Alfred Hospital, Sydney.

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    A day in the life of Mr Saha involves seeing patients in clinic, operating in surgical theatre or lecturing at his university. He also regularly teaches and presents at vascular and sports medicine conferences.

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    Consultant Partner, LBSM
    Consultant in Sports and Musculoskeletal Radiology

    Dr Gajan Rajeswaran is a Consultant Musculoskeletal Radiologist at LBSM, with an extensive background of working in elite sport. He is one of the most recognised radiologists in the sports medicine field. He provides top level imaging and medical diagnostic services for patients and athletes.

    Dr Gajan Rajeswaran completed his undergraduate medical training at Imperial College London and his radiology training at Chelsea & Westminster Hospital. He has obtained two post-CCT fellowships in musculoskeletal imaging. He was appointed as a consultant at Chelsea & Westminster Hospital in 2011.

    He has a passion for all sports having worked as a radiologist at the Glasgow Commonwealth Games and London World Athletic Championships and continues to support The Championships, Wimbledon. He also continues to work with a number of Premier League and Championship Football Clubs, Premier League Rugby Clubs, England Sevens Rugby, British Athletics and the Lawn Tennis Association.

    A day in the life of Dr Rajeswaran involves giving his expert opinion on investigations such as MRI and CT scans, x-rays and ultrasound. He also performs injection lists under ultrasound, CT and X-ray including spinal injections. He also regularly teaches and presents at sports medicine conferences.

    Dr Gajan Rajeswaran is an avid football fan and life-long fan of Tottenham Hotspur (for which he offers no apologies!). Outside of work, he spends time with his family and has a keen passion for photography.

    Dr Ajai Seth
    Medical Director, LBSM
    Consultant in Sport and Exercise Medicine

    Dr Ajai Seth is a Sport and Exercise Medicine Physician. He has dedicated his career to helping people with sport and exercise related injury and illness. He consults and treats everyone from the elite athlete to the weekend warrior.

    Dr Ajai Seth is part of the British Tennis Sports Physician team at the LTA and has also provided cover to elite athletes at Wimbledon Tennis, European Tour Golf, Premier League Football, British Athletics, and the Men’s England Football academies as part of the FA.

    He also prides himself for working in disability sport and is currently the Chief Medical Officer for Team GB Wheelchair Tennis which has taken him to the Olympics and Paralympics.

    Dr Ajai Seth is dedicated to education, training and research and is a Senior Lecturer in Sports Medicine at King’s College London where he lectures in all aspects of Sports Medicine and Science.

    He also has a passion for travel and Expedition Medicine, which has seen him accompany medical, scientific and charity expeditions all around the world. He also has vast experience in treating musculoskeletal injuries from children and adolescents to veteran exercisers, both male and female.

    Dr Seth also has positions in leading Sport Medicine organisations, including the non-executive board for the UK’s largest Sports Medicine charity, BASEM and Past President for the Royal Society of Medicine. 

    A day in the working life of Dr Seth involves consulting his patients in clinic, performing diagnostics and ultrasound guided injections. He also regularly lectures and tutors students and presents at sports medicine conferences internationally. He also spends part of the working week at the National Tennis Centre, LTA, supporting British Tennis players.

    Outside of work, Dr Seth enjoys playing club tennis, triathlon, golf, running and skiing (but will give any sport a go!). He enjoys keeping fit and active and good quality family time with his wife and three children.