They argue that "universal conclusions about its benefits cannot be drawn" and say further studies and better designed trials are needed.

A growing body of evidence indicates that vitamin D may reduce risks of a wide range of diseases, including bone mineral disease, multiple sclerosis, autoimmune disorders, cancer and cardiovascular problems. Yet, despite hundreds of trials, the evidence for vitamin D is still being debated.

Two papers published on bmj.com today attempt to make sense of the existing data.

These findings differ from previous smaller trials and do not support a general recommendation for the use of probiotics to treat colic in infants.

Infant colic (excessive crying of unknown cause) affects up to 20% of infants and is a major burden to families and health services. Although it spontaneously resolves three to four months after birth, its cause remains elusive and no single effective treatment exists.

Previous small trials suggest that the probiotic Lactobacillus reuteri effectively treats colic in breastfed infants. These studies, however, had limitations as they examined only a highly selective group of infants with colic. The effects of L reuteri on formula fed infants with colic are unknown.

The amount of water present in the moon may have been overestimated by scientists studying the mineral apatite, according to a new computer model created to accurately predict how apatite would have crystallized from cooling bodies of lunar magma early in the moon's history. Their simulations revealed that the unusually hydrogen-rich apatite crystals observed in many lunar rock samples may not have formed within a water-rich environment, as was originally expected.  

Writing in Science, the authors say this discovery has overturned the long-held assumption that the hydrogen in apatite is a good indicator of overall lunar water content.  

Can you buy ethics? Are scientists simply paid guns producing research for anyone that writes a check?

It's certainly a common cultural belief. Skeptics about global warming think that academics cozy up to politicians and apply for grants related to whatever is in the news while skeptics about medicine believe that if a researcher gets funding from anywhere except the government they are for sale. In reality, there is more disclosure and less conflict of interest that at any point in the history of science. There was a time when scientists had to read Tarot cards and make astrology charts for wealthy patrons and people who know how expensive and difficult drug discovery is dread a future where the government does it rather than corporations.

Oxytocin, the love hormone, is correlated to everything from maternal attachment to sexual addiction. Now it has been implicated in lying.

Oxytocin is a hormone the body naturally produces to stimulate bonding and psychologists from Ben-Gurion University of the Negev (BGU) and the University of Amsterdam say it even causes participants to lie more to benefit their groups. People do so more quickly and without expectation of reciprocal dishonesty from their group, they write in the Proceedings of the National Academy of Science (PNAS).

Why zebras have black and white stripes is a long-standind puzzle of evolution.

To find out, the researchers behind a Nature Communications paper mapped the geographic distributions of the seven different species of zebras, horses and asses, and of their subspecies, noting the thickness, locations, and intensity of their stripes on several parts of their bodies. Their next step was to compare these animals' geographic ranges with different variables, including woodland areas, ranges of large predators, temperature, and the geographic distribution of glossinid (tsetse flies) and tabanid (horseflies) biting flies.

They then examined where the striped animals and these variables overlapped.