A report in Circulation: Journal of the American Heart Association finds that after two decades of improvement, the percentage of Americans without major heart disease risk factors is dropping, and is currently less than 10 percent.

The lead author of the study, Dr. Earl Ford, says for most United States adults achieving low-risk status is a “distant and challenging” goal. He adds that the strides made in the past few decades have been “eroded by the increases in excess weight, diabetes and hypertension.”

The report, which examined data from several national surveys on low-risk adults, finds women are more likely than men to be considered low risk. White people also had lower risk than both African Americans and Mexican Americans.

Low-risk criteria includes not smoking, having total cholesterol below 200 mg, having blood pressure below 120/80 and having never been diagnosed with diabetes.

Natural therapies, including exercise, a low-fat diet and taking nutritional supplements containing omega-3 fatty acids may further lower the odds of developing heart disease.

The alkaline diet, which is rich in citrus fruits, vegetables, tubers, nuts and legumes may also be beneficial.