By Sheryl Wood
Consuming lots of sugary drinks can expand your waistline, but you may not be aware of what it also might do to your blood pressure.
Sugar is added to many food products, but the largest source of added sugar we consume is in sugar-sweetened drinks.
Drinking sugar-sweetened beverages has been linked to obesity, high blood sugar, heart disease and kidney stones. Recently published researched found it was also associated with increased blood pressure and a greater risk for developing hypertension (high blood pressure).
Aaqib Habib Malik, MD, BSc, MPH, from the Department of Internal and Preventive Medicine at Griffin Hospital and the Connecticut Yale-Griffin Prevention Research Center of Derby, Connecticut, and a team of researchers conducted this study.
The researchers analyzed 12 previously published studies that reported on the effects of consuming sugar-sweetened beverages on blood pressure. The studies included 409,707 people aged 12 years and older.
The studies showed a 26 to 70 percent increased risk of developing high blood pressure in people who consumed sugar-sweetened beverages compared to people who did not drink sugar-sweetened beverages.
One of the studies on teenagers found an 87 percent increase in risk of developing high blood pressure in those who drank sugar-sweetened beverages three or more times a day compared to teens who did not drink sugar-sweetened beverages.
High blood pressure was 16 to 60 percent more common in the group of people who consumed greater amounts of sugar-sweetened beverages than in people who did not drink these beverages.
The link between increased consumption of sugar-sweetened beverages and hypertension was not dependent on age, and this link became stronger after 18 months of increased sugary beverage consumption.
A limitation of the analysis by Dr. Malik’s team was that it could only show an association between sugar-sweetened beverage consumption and blood pressure and not that sugar-sweetened beverages were the cause of the higher blood pressure.
The researchers explained the significance of small differences in blood pressure by saying that lowering the upper number in a blood pressure reading by two points can reduce stroke deaths by 10 percent. The upper number, called the systolic pressure, in a blood pressure reading measures the pressure in the arteries when the heart beats. A normal systolic pressure reading is less than 120.
“All 12 studies showed positive relation between increased [sugar-sweetened beverage] intake and hypertension,” the study's authors wrote.
These authors put forth several theories of how sugar-sweetened beverages might increase blood pressure. Sugar-sweetened beverages can lower nitric oxide in the body, causing blood vessels to constrict and blood pressure to rise. Sugar-sweetened beverages can contain extra salt, and studies have also shown that people with increased sugar consumption also tend to eat more salt. Salt can cause changes in the body that raise blood pressure.
Carolyn Dean, MD, ND, from the Medical Advisory Board Member of the non-profit Nutritional Magnesium Association, commented, "A fascinating and little-known fact about sugar metabolism is that 28 molecules of magnesium are required to metabolize one molecule of sucrose (table sugar) and 56 molecules of magnesium are used up to metabolize one molecule of fructose (fruit sugar).
"When magnesium is diminished to that extent, the resulting magnesium deficiency can contribute to raising the blood pressure because magnesium is required to relax the muscles of the body, including the smooth muscles of the blood vessels. If there is tension in the smooth muscles of the blood vessels, then blood pressure rises," Dr. Dean explained.
"Studies have shown that diets deficient in magnesium will produce hypertension — sugary drinks contribute to creating a magnesium deficiency in the body and and a corresponding rise in blood pressure. And 75 percent of Americans do not get nearly the [recommended daily allowance] of magnesium from their diets," she said.
"Other studies have shown that increased levels of minerals such as potassium and magnesium in the diet have a suppressive effect on calcium-regulating hormones, which helps lower blood pressure," she explained.
Dr. Dean concluded by saying, "Magnesium is a natural statin (anticholesterol medication). It is necessary for the activity of an enzyme that lowers bad cholesterol (LDL) and triglycerides and raises good cholesterol (HDL). Because magnesium has been depleted from our soils and food processing, it is difficult to get enough from our foods. As a supplement, one of the most absorbable forms of magnesium is powdered magnesium citrate, which can be mixed with water."
Dr. Malik and team wrote, “It remains unclear at what dose increased [sugar-sweetened beverage] intake leads to development of hypertension. On the basis of these studies, although, there is a suggestion that intake of [more than one] serving of [sugar-sweetened beverages] per day is associated with higher risk of hypertension.”
“Restriction on [sugar-sweetened beverage] consumption should be incorporated in the recommendations of lifestyle modifications for the treatment of hypertension,” the authors advised.
This study appears in the May 2014 issue of the American Journal of Cardiology.
The authors declared no conflicts of interest.