Hate the taste of broccoli? Do you perceive honey as too sweet? According to a new study, a common gene variant should be blamed for our food choices.

The McGill-led research team has recently discovered that for girls who are carriers of a particular gene variant (DRD4 VNTR with 7 repeats), the crucial element that influences a child's fat intake is not the gene variant itself.

Instead, it is the interplay between the gene and girls' early socio-economic environment that may determine whether they have increased fat intake OR healthier than average eating compared to their peers from the same class background. The DRD4 repeat 7 is found in approximately 20 per cent of the population and is known to be associated with obesity, especially in women.

Lead researcher Laurette Dube said that they found that among girls raised in poorer families, those with DRD4 repeat 7 had a higher fat intake than other girls from the same socio-economic background, but they also found that girls with exactly the same gene variant who came from wealthier families, compared to these with the same economic conditions, had a lower fat intake.

Dube noted that this suggests that it's not the gene acting by itself, but rather how the gene makes an individual more sensitive to environmental conditions that determines "for better or worse" a child's preference for fat and consequent obesity as the years pass by.

Interestingly, the researchers found this effect to be true only in the girls that they tested. They speculate that this may be because, from an evolutionary standpoint, it may have been more important for girls to be able to gain weight easily to adapt to adverse conditions in order to reproduce.

Another possibility they advance is that at age four, it may simply be too early to see these effects in boys since boys and girls gain weight at different stages at this age, and may also have different behavioural responses to hunger and feelings of satiety.

These results underscore the importance of moving beyond a 'one-size-fits-all' approach to childhood obesity prevention, said Dube, adding "we need to move towards targeted approaches that focus on populations that are particularly vulnerable to both genetic and environmental factors: those who are biologically more vulnerable under adverse environments are those likely to be more responsive to improvements in their conditions."

The study appears in JAMA Pediatrics.

Since the Nobel Prize-winning discovery of the enzyme telomerase in 1984, identifying other biological molecules that lengthen or shorten the protective caps on the ends of chromosomes has been slow going.

A new Maharishi University of Management study found that the Transcendental Meditation technique and lifestyle changes both appear to stimulate genes that produce telomerase, an enzyme that's associated with reduced blood pressure, cardiovascular disease and mortality.

Specifically, these approaches were found to activate two genes that code for telomerase, which adds molecules to the ends of chromosomes, or telomeres, protecting them from deteriorating.

The finding that telomerase gene expression is increased and that this is associated with a reduction in blood pressure in a high-risk population, suggests that this may be a mechanism by which stress reduction improves cardiovascular health, said coauthor Robert Schneider.

The new study examined what was happening at the level of DNA, showing that the Transcendental Meditation technique increases telomerase gene expression and suggesting that this may contribute to the cardiovascular and aging benefits.

Coauthor Otelio Randall of Howard University College of Medicine concluded this pilot study in African Americans suggests stress reduction and lifestyle modifications may reduce blood pressure with an increase in telomerase.

The study appears in PLOS ONE.

For people suffering from glaucoma, certain yoga positions - especially head-down postures - and other exercises like push-ups and lifting heavy weights may be dangerous, a team of US researchers has warned.

Glaucoma patients may experience increased eye pressure as the result of performing several different head-down positions while practicing yoga, claimed the researchers from New York Eye and Ear Infirmary of Mount Sinai (NYEE).

Four inverted yoga positions - facing dog, standing forward bend, plow and legs up the wall - were key to the research.

"While we encourage our patients to live active and healthy lifestyles, certain types of activities, including pushups and lifting heavy weights, should be avoided by glaucoma patients," said Robert Ritch, senior study author and Director, Glaucoma Research, NYEE.

Damage to the optic nerve occurs in glaucoma patients when fluid pressure inside the eye rises. Elevated intraocular pressure (IOP) is the most common known risk factor.

Certain yoga postures and exercises increase "the risk of increasing IOP and possibly damaging the optic nerve," Ritch noted.

In previous research, studies and case reports had tested only the headstand position which showed a marked two-fold rise in IOP.

In the new study, researchers asked healthy participants with no eye-related disease and glaucoma patients to perform four inverted yoga positions.

Both normal and glaucoma study participants showed a rise in IOP in all four yoga positions, with the greatest increase of pressure occurring during downward facing dog.

When the measurements were taken after the participants returned to a seated position and again after waiting for 10 minutes, the pressure in most cases remained slightly elevated from the baseline.

"As we know that any elevated IOP is the most important known risk factor for development and progression of nerve damage to the eye, the rise in IOP after assuming the yoga poses is of concern for glaucoma patients and their treating physicians," explained study first author Jessica Jasien at NYEE.

"In addition, glaucoma patients should share with their yoga instructors their disease to allow for modifications during the practice of yoga," Jasien added.

The research team emphasises the importance of educating glaucoma patients on all of the risks and benefits of relating to physical exercise and their overall vision health.

"The new study will help clinicians advise their patients on the potential risk associated with various yoga positions and other exercises that involve inverted poses," the authors concluded in a paper published in the journal PLOS ONE.

A new study has debunked the widespread belief that radiations from X-rays and CT scans can cause cancer.

Scientists said that it is time to hurl away an unproven, decades-old theoretical model that has led many people, including doctors to believe otherwise.

Scientists used a model known as linear no-threshold (LNT) to estimate cancer risks from low-dose radiation such as medical imaging.

But, risk estimates based on this model are only theoretical and, as yet, have never been conclusively demonstrated by empirical evidence, they said.

The use of LNT model drives unfounded fears and excessive expenditures on putative but unneeded and wasteful safety measures, according to James Welsh, a professor at the Loyola University Chicago Stritch School of Medicine in US.

The LNT model dissuades many physicians from using appropriate imaging techniques and "discourages many in the public from getting proper and needed imaging, all in the name of avoiding any radiation exposure," Welsh and colleagues wrote in the study published in the American Journal of Clinical Oncology.

The said that the LNT model assumes there is no safe dose of radiation, no matter how small. However, the human body has evolved the ability to repair damage from low-dose radiation that naturally occurs in the environment.

They said that studies of atomic bomb survivors and other epidemiological studies of human populations have never conclusively demonstrated that low-dose radiation exposure can cause cancer.

Any claim that low-dose radiation from medical imaging procedures is known to cause cancer "should be vigorously challenged, because it serves to alarm and perhaps harm, rather than educate," they said.

The researchers suggested that the LNT model "should finally and decisively be abandoned."

The researchers reexamined the original studies, dating back more than 70 years, which led to adoption of the LNT model.

US researchers have found a new sunscreen that guarantees no loss of vitamin D, rather allows the body to produce the essential vitamin, a deficiency or insufficiency of which causes major health problems in both adults and children.

Researchers from Boston University in the US developed Solar D, through a process in which the ingredients of a sunscreen are altered in such a way that it does not impact its sun protection factor (SPF), but does allow the body to produce vitamin D.

"Solar D was designed with compounds with differing filter compositions to maximise vitamin D production while maintaining its sun protection for reducing erythema or burning of the skin," said Michael F. Holick, professor at Boston University.

Sun exposure has been the major source of vitamin D for most children and adults worldwide.

However, the increased risk of skin cancer led to the widespread usage of sunscreens.

As a result, an SPF of 30 when properly applied reduces the capacity of the skin to produce vitamin D by almost 98 percent, the researchers said.

There are several chemical compounds that are typically used in a sunscreen that efficiently absorbed varying wavelengths of UVB radiation, the researchers explained in the study published in the journal PLOS ONE.

After removing certain ingredients the researchers compared Solar D, which has an SPF of 30, to a popular commercial sunscreen with the same SPF, and found Solar D allowed for up to 50 percent more production of vitamin D in-vitro.