If you’re trying to boost your calcium intake, it’s probably better to consume more dairy products and leafy greens than take a calcium supplement. A US government-funded study has concluded that taking calcium in the form of supplements may raise the risk of plaque build-up in arteries and heart damage, although a diet high in calcium-rich foods appears be protective.
A team from six US universities analysed 10 years of dietary questionnaires and medical tests on more than 2,700 people aged 45 to 84, among whom 12 per cent were Chinese and 41 per cent were white.
The researchers, however, caution that their work only documents an association between calcium supplements and atherosclerosis, and does not prove cause and effect. Their report was published on October 10 in the Journal of the American Heart Association. They urge a consultation with a knowledgeable physician before using calcium supplements.
After adjusting the data for age, sex, race, exercise, income, education, weight, smoking, drinking, blood pressure, blood sugar and family medical history, the researchers separated out 20 per cent of participants with the highest total calcium intake, which was greater than 1,400 milligrams of calcium a day. That group was found to be on average 27 per cent less likely than the 20 per cent of participants with the lowest calcium intake (less than 400 mg of daily calcium) to develop heart disease, as indicated by their coronary artery calcium test.
Supplement users (about 46 per cent of the study population) showed a 22 per cent increased likelihood of having their coronary artery calcium scores rise higher than zero over the decade, indicating development of heart disease. Among participants with the highest dietary intake of calcium (over 1,022 mg per day) there was no increase in relative risk of developing heart disease over the 10-year study period.
Some children are genetically predisposed to overeating in response to ads
Exposure to food ads on TV leads to overeating among children, especially those genetically predisposed to obesity, according to researchers at Dartmouth College in the US. In a randomised experiment, 172 children aged nine or 10 ate lunch until they were full and then were immediately shown a 34-minute television show that contained either food or toy advertisements at normal commercial breaks. The children were given snacks that they could eat while watching the show. The researchers then measured how much the children ate and tested them for genetic variations in the gene known as FTO that is associated with fat mass and obesity.
Children who watched food advertisements consumed an average of 41 per cent more calories of a recently advertised food than those who watched ads for toys. The effect of food ads on overeating differed by FTO genotype, with the effect more than three times as large for children at the highest genetic risk.
“This study shows that children overeat in response to TV food ads even when they are not hungry. More importantly, some children are genetically prone to eat much more in response to those cues,” says researcher Diane Gilbert-Diamond. “The findings may help us understand how genes predispose people to obesity by amplifying the response to environmental food cues. If that finding is confirmed, limiting exposure to food advertising and other food cues would be key to combating child obesity.”
Strenuous exercise is unlikely to prolong labour or increase risk of premature birth
Should athletes used to strenuous exercise continue their regime after getting pregnant? A new consensus statement from the International Olympic Committee and published online in the British Journal of Sports Medicine says strenuous exercise during pregnancy is unlikely to prolong labour or boost the risk of premature birth. However, the overall quality of the available evidence on the impact of intense exercise is not strong, with few studies carried out on elite athletes, the statement warns.
Elite athletes planning pregnancy are advised to consider reducing high-impact training routines in the week after ovulation and refraining from repetitive weight training during the first three months of pregnancy, as some evidence suggests this may be linked to a heightened risk of miscarriage.
Baby birthweights of exercising women are less likely to be excessively large (more than 4kg) and not at increased risk of being excessively small (less than 2.5kg). There is some encouraging evidence that women who exercise regularly throughout pregnancy have a shorter first stage of labour (before full dilatation) and may reduce the need for caesarean sections.
There is little risk of abnormal fetal heart rate response when elite athletes exercise at below 90 per cent of their maximal heart rates in the second and third terms of pregnancy. Exercise during pregnancy does not increase the risk of induced labour; epidural anaesthesia; episiotomy or perineal tears; or forceps or vacuum deliveries.
The statement draws on a systematic review of the available published evidence, presented by an international panel of experts in Lausanne, Switzerland, in September 2015.