HEALTH news in brief

Low-fat diet better than low-carb one; trans-fats the culprit for heart disease

PUBLISHED : Sunday, 16 August, 2015, 10:01pm
UPDATED : Sunday, 16 August, 2015, 10:01pm

Saturated fats aren't that bad after all, according to a new study review by McMaster University in Ontario, Canada. Published in the British Medical Journal, the study found saturated fats - contrary to popular belief - are not linked with an increased risk of death, heart disease, stroke, or type 2 diabetes. Trans fats, however, are associated with greater risk of death and coronary heart disease. "That said, we aren't advocating an increase of the allowance for saturated fats in dietary guidelines, as we don't see evidence that higher limits would be specifically beneficial to health," says lead researcher Russell de Souza. Saturated fats come mainly from animal products such as butter, cows' milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils. Trans fats are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods. Guidelines currently recommend that saturated fats are limited to less than 10 per cent, and trans fats to less than 1 per cent of energy, to reduce risk of heart disease and stroke.

Fresh eggs better than frozen for in vitro fertilisation: Using fresh eggs for in vitro fertilisation, rather than frozen ones, was associated with higher live birth rates, according to a study based on US data from 2013 published in the journal JAMA. The data is based on centre-specific voluntarily reported outcomes from 380 of 467 (81 per cent) US-based fertility centres, which, in 2013, collectively performed 92 per cent of all IVF cycles. Of 11,148 egg donation cycles, 20 per cent involved use of frozen donor eggs. Initiated cycles were cancelled in 12 per cent of fresh egg cycles compared with 8.5 per cent of frozen egg cycles. Per started recipient cycle, the live birth rates were 50 per cent with fresh vs 43 per cent with frozen eggs. Per embryo transfer, the live birth rates were 56 per cent with fresh compared with 47 per cent with frozen eggs. The reasons remain to be established. "One possible explanation is less opportunity for proper embryo selection due to smaller starting numbers of oocytes [eggs], leading to fewer embryos available for transfer. Alternatively, oocyte quality may be negatively affected by cryopreservation and thawing," the researchers say.

Low-fat diet works better than a low-carb one: Cutting fats or restricting carbs: which is better for losing body fat? A new study from the National Institutes of Health in the US shows cutting fats is more effective, even though a low-carb diet reduces insulin and increases fat burning. Published last week in Cell Metabolism, the researchers confined 19 consenting adults with obesity to a metabolic ward for a pair of two-week periods, during which all food eaten was controlled. In the first period, 30 per cent of baseline calories were cut through carb restriction alone, while fat intake remained the same. During the second period the conditions were reversed. At the end of the two dieting periods, the mathematical model proved to be correct. Body fat lost with dietary fat restriction was found to be greater compared with carbohydrate restriction. But the researchers predict over prolonged periods the body acts to minimise body fat differences between the two diets. They recommend that for now, the best diet is the one that you can stick to.