The blood vessels of obese and overweight adults are characterized by increased activity of endothelin (ET)-1, a protein that constricts the small vessels. Heightened activity of ET-1 makes the blood vessel less responsive to blood flow demand and increases a person's risks to develop vascular diseases.
Exercise is known to reduce ET-1 activity but while individuals with weight problems are advised to exercise to improve their health, researchers said that more than half do not engage in physical activities.
Findings of a new research, however, suggest an option for overweight and obese individuals who have sedentary lifestyle.
For the study, which was presented at the American Physiological Society's 14th International Conference on Endothelin held in Savannah, Georgia, Caitlin Dow, from the University of Colorado, Boulder, and colleagues sought to know if intake of vitamin C supplements reported to improve vessel function can reduce ET-1 activity so they involved 35 sedentary and overweight and obese adults.
The participants all have impaired vascular tone at the start of the study. The condition causes inflammation and makes the blood more susceptible to blood clots, which make the participants at risk of developing heart disease.
After three months, the researchers found that taking 500 mg of vitamin C supplements daily reduced ET-1 related vessel constriction as much as walking did. The researchers likewise found that while neither of the participants in the Vitamin group and the exercise group lost weight, exercise and daily vitamin C intake helped return the participants' vascular tone to normal.
Dow said that vitamin C is not an exercise pill but noted that the findings are important for individuals who cannot exercise because of physical limitations. She said that compared with vitamin C, regular physical activities still have more beneficial effects such as improving metabolic function, lowering bad cholesterol levels and improving cognitive function so those who can get up and walk should consider exercise as a healthier option.
"If we can improve different measures of risk for disease without changing weight, it takes a little bit of the pressure off some people," Dow said. "It's important to know what other lifestyle changes we can offer people who can't exercise."
The 500 mg vitamin C used in the study is considered as a relatively high dose. Common unwanted effects of high doses of vitamin c include nausea, abdominal cramps, diarrhea and gastrointestinal disturbances.
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