A study was carried out by Swedish researchers to evaluate the long- term consequences of low carbohydrate, high protein diet on cardiovascular health.
Obesity is prevalent all over the world, but not many obese people are aware of the fact that they are at risk for several common chronic diseases. Although exercise is recommended to reduce weight by burning the excess food consumed, it is also very important to 'watch calories' and reduce one's food intake. It is precisely for this reason that various diets, invoking increased satiety, have been proposed as a sure-fire method for weight reduction.
AdvertisementOne such diet that has gained immense popularity is the low-carbohydrate, high-protein diet. High fats are usually avoided in most western societies, especially by the weight -watchers. Low carbohydrate-high protein diet may help in weight reduction, but concerns have been raised by many regarding its effect on cardiovascular health outcomes.
Ideally, low carbohydrate-high protein diets may be nutritionally acceptable if only simple and refined carbohydrates are avoided or if the protein is mainly of plant origin. However, the general public are not aware of all this and may avoid food that is essential to them or consume more of that food which needs to be minimized.
A random population sample study was carried out on Swedish women, aged between 30-49 years, living in the Uppsala health care region in Sweden. They were randomly grouped into four age strata 30-34, 35-39, 40-44 and 45-49. Around 49 261 volunteers participated in the study by filling questionnaires, which recorded information on smoking, alcohol intake, anthropometry and history of diagnoses of major diseases and conditions, including hypertension. For the assessment of physical activity, the women were asked to rate themselves on a five point scale.
Dietary intake was evaluated with the help of food frequency questionnaire, in which the consumption of approximately 80 food items and beverages were recorded, with focus given on food consumed six months prior to the study. Eleven food groups were formed including vegetables, legumes, nuts and fruits, dairy products, cereals, meat and meat products, fish and seafood, eggs, potatoes, sugars and sweets and non-alcoholic beverages. Alcoholic beverage formed a separate category.
The subjects were followed up, with focus given on the incidence of CVD. The results revealed that both high protein and low carbohydrate diet were significantly responsible for an increased incidence of cardiovascular diseases. The high protein diet was responsible for the occurrence of ischemic heart disease and ischemic stroke.
During the course of the study, 1270 incident cardiovascular events were recorded. It was found that a 20 g decrease in daily carbohydrate intake and a 5 g increase in daily protein intake would increase the overall risk for cardiovascular disease in an individual by 5 %.
Vegetables, fruits, cereals, and legumes are important sources of carbohydrates. Hence, reduced intake of these foods may have an adverse effect. The study is extremely relevant, as it has been carried out on a group of young women who belong to an age group that is likely to follow diet control regimens that encourage low carb, high protein intake.
This research has thus succeeded in drawing attention to the possible cardiovascular health risks these diets pose when the individuals do not take into account the nature of carbohydrates (complex / refined) or the protein source (plant /animal) before they embark on weight-loss regimes.
Low carbohydrate-high protein diet and incidence of cardiovascular diseases in Swedish women: prospective cohort study; Pagona Lagiou et al; BMJ 2012;344:e4026