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.
One 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.
protein diet was responsible for the occurrence of ischemic heart disease and
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
Low carbohydrate-high protein diet and
incidence of cardiovascular diseases in Swedish women: prospective cohort
study; Pagona Lagiou et al; BMJ 2012;344:e4026