According to the World Health Organization, added sugars should not exceed 10% of our daily energy intake. For an average adult who consumes 2000 calories per day, this represents 200 calories, or 50 g or 12 spoonfuls of sugar.
This limit can be very difficult to respect when eating industrially processed foods on a daily basis. Perhaps the worst example is soft drinks, with over 40g of sugar per can.
But even foods such as cereals, yogurts, breads, sauces or salad dressings also contain significant amounts of added sugars. The only realistic way to limit your added sugar intake is therefore to cook yourself and limit the consumption of industrial products as much as possible, especially those offered by the junk food and soft drink industry.
Because excess sugar causes severe health problems. For example, one study showed that people who consume more than 10% of their calories in the form of added sugars are 30% more likely to die prematurely from cardiovascular disease. This increased risk even reaches 275% in those for whom sugar represents more than 25% of their daily calories.
It seems that this negative effect is mostly caused by excess fructose. Added sugars are generally made up of 50% glucose and sucrose (table sugar), and 50% fructose. In both cases, excessive sugar consumption leads to a massive intake of fructose.
What is problematic for our metabolism: fructose is stored by the liver where it is transformed into fat, which leads to significant imbalances in blood lipids and an increased risk of cardiovascular disease.
Sugar: an increase in the incidence of breast cancer by 50%
In addition to its detrimental effect on heart function, data suggests that excess sugar may also increase the risk of certain cancers. For example, postmenopausal women who consume the most added sugars see their risk of hormone-independent breast cancer increase by about 50%.
To better understand this phenomenon, a team from the MD Anderson Cancer Center in Texas examined the impact of sucrose on the progression of breast tumors in experimental models.
They observed that ingesting an amount of sugar equivalent to what is consumed in the West caused a marked increase in the incidence of breast tumors, as well as an increase in their ability to spread in the form of metastases.
This pro-cancer effect of sugar is due to an increase in the activity of 12-lipooxygenase, an enzyme involved in the inflammatory response and which therefore creates a climate of inflammation conducive to the progression of cancer cells.
The increase in inflammation as well as the accelerated progression of breast tumors are observed when sucrose is replaced by fructose, suggesting that the pro-cancer effect of added sugars is mainly due to excess fructose.
Less sugar, more fiber
There is therefore no doubt that a reduction in the intake of foods containing added sugars is extremely positive for health. A beneficial effect which will be all the more pronounced if this reduction is combined with an increase in the intake of foods known to reduce the risk of cancer, in particular plants.
For example, a recent study showed that young women who regularly consumed fiber, both soluble and insoluble, saw their risk of breast cancer decrease by 15%.
Yang Q et al. Added sugar intake and cardiovascular disease mortality among US adults. JAMA Intern Med. ; 174:516-24.
Romieu I et al. Dietary glycemic index and glycemic load and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC). Am J Clin Nutr. 96: 345-55. Jiang Y et al. A sucrose-enriched diet promotes tumorigenesis in mammary gland in part through the 12-lipoxygenase pathway. Cancer Res.; 76: 24-9. Farvid MS et al. Dietary fiber intake in young adults and breast cancer risk. Pediatrics 137: e20151226.