Not only does vitamin D work with calcium to keep bones strong, but researchers now found that teenage girls with higher vitamin D levels may be able to jump higher and faster than their peers with lower levels, according to a new study published in the Journal of Clinical Endocrinology and Metabolism .

UK researchers collected vitamin D levels for 99 girls, ages 12 to 14. To test the girls' muscle function, the girls were instructed to jump as high as possible while researchers used a device designed to measure power and performance called jumping mechanography. After controlling for differences in the girls' body weight, the girls with the highest vitamin D levels had the highest jump speeds, jump height, power and force.

This potential muscle advantage adds to the growing list of evidence positioning vitamin D as a super nutrient. Well known for its role in keeping bones strong, vitamin D is now being hailed for so much more. Emerging science suggests vitamin D may also help protect against diabetes, hypertension, heart disease and certain cancers. It may also support a healthy immune system to ward off infections, and some preliminary evidence suggests it may affect longevity.

Yet despite a potential upside of boosting vitamin D levels, Americans of all ages still fall short of their vitamin D needs. Even in this study with demonstrated muscle benefits, overall, the girls' vitamin D levels were far less than ideal “ a finding consistent with numerous studies indicating a resurgence in vitamin D deficiencies in adolescence. In fact, current deficiency levels prompted the American Academy of Pediatrics to double the vitamin D recommendations for children and teens to 400 IU daily. The Academy estimates that up to half of adolescents have low vitamin D levels.

The recommended three glasses of lowfat or fat free milk a day delivers 75 percent of the vitamin D that's needed each day. Milk remains the leading source of vitamin D in the American diet “ it's one of the few food sources of the super nutrient. Plus, along with vitamin D, milk is a good source of calcium and high-quality protein “ two nutrients vital to help teens maintain bone density and lean muscle.

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Some claim you can lose weight effortlessly in weeks rather than months or years but Choice says such fast-track diets fail to address the real issues at the root of the weight problem and questions who ends up profiting the most.

All the pharmacy plans involved a weekly visit to the pharmacy 'consultant' and a diet that to some extent restricted carbohydrates.

The diet programmes looked at were:

AlphaSlim Pharmacy Weight Loss Betty Baxter Complete Weight Management Dr. Tim's Success Kate Morgan Weight Loss MediTrim Tony Ferguson Weight Loss Ultra Lite Weight Management Xndo Weight Control System

All except Ultra Lite use meal replacements to keep intake in check but while this approach is sometimes used by doctors and dieticians in hospitals and clinics to treat obese and very obese people, whose health is seriously at risk, these people usually have health problems, such as heart disease or high-blood pressure, and have failed to lose weight using other approaches.

Choice says meal replacements are also often used before weight-loss surgery, such as gastric banding and are most likely to be effective under close medical supervision and along with effective counselling on long-term diet, lifestyle, behavioural and psychological issues.

Choice says this is the critical area where pharmacy-based meal replacement programmes fall short and in view of the inadequate training of consultants, little ability to tailor programmes and deal with individual circumstances and habits, as well as the lack of close, qualified supervision, they cannot recommend these programmes.

Choice says the current regulations and voluntary codes of practice covering weight-loss programmes are insufficient and a national accreditation system is called for, including minimum standards for training, covering all programmes, consultants and those who counsel people on losing weight.