Yang Wenjiao, a Beijing-based nutritionist, said that an individual's blood cholesterol level was largely dependent on genetic and metabolic factors. For an ordinary healthy adult, the effect of consuming more or less cholesterol in food was relatively small.
"Adolescents and healthy adults, who have an active metabolism and strong constitution don't need to limit their cholesterol intake," said Yang. "If they consume more high cholesterol foods, their bodies can detect the amount of cholesterol they are consuming, and automatically produce less cholesterol to maintain a healthy balance."
It was only for older people and people who had health problems such as hyperlipidemia (elevated lipid levels in the blood) that needed to monitor and restrict cholesterol intake, said Yang.
'Good' and 'bad' cholesterol
Lü Shuzheng, director of the cardiology department at Beijing Anzhen Hospital, noted in a 2013 Xinhua News Agency report that it was important to distinguish between "good" cholesterol (high density lipoprotein cholesterol, or HDL-C) and "bad" cholesterol (low density lipoprotein cholesterol, or LDL-C).
"Good" cholesterol helps balance the total amount of cholesterol in a person's blood and prevents the accumulation of fatty acids in blood vessels, while "bad" cholesterol tends to accumulate in the arterial vascular wall, inhibiting blood circulation and increasing the risk of cardiovascular diseases such as blood clots, heart problems and stroke, said Lü.
However, a small amount of "bad" cholesterol was also necessary, said Lü, to generate muscle mass after physical exercise.
Common tests for blood lipids measure four indexes, distinguishing between a person's triglyceride level, total blood cholesterol level, and his/her "good" and "bad" cholesterol levels.
A report on the Prevention of Cardiovascular Disease published by the World Health Organization in 2007 noted that people with a total cholesterol above 8 millimoles per liter, a HDL-C above 8 millimole per liter, or a LDL-C above 6 millimole per liter were considered to be at a greater risk of cardiovascular diseases.
However, Yang said that it was unnecessary for healthy adults to fret too much about their cholesterol intake, as cholesterol is a naturally regulated substance produced by the body that serves a number of vital functions.
"Cholesterol is an important constitutive substance of cell membranes and nerve fibres, as well as helping produce vitamin D, bile acid, sex hormones and adrenocortical hormones," said Yang. "['Good' cholesterol] helps digest excess fat, and keep the blood vessel wall healthy."
Other factors
Ma said that there was no direct evidence connecting cholesterol intake to cardiovascular diseases.
"A 16-year-long study conducted in Japan [published in the Journal of the American Heart Association in 2012] showed that people with a low daily cholesterol intake, between 150-200 milligrams, were twice as likely to die from a heart disease than those who had a high daily intake, above 300 milligrams," said Ma. "The research also showed that there is no link between daily cholesterol intake and the likelihood of stroke."
Cai Honglin, a nutritionist at Wuhan Union Hospital in Hubei Province, said in a People's Daily report in 2012 that in terms of cardiovascular health, the key was to lower the amount of "bad" cholesterol, which was more dependent on living a healthy life style than reducing cholesterol intake from one's diet.
"Factors that increase the risk of cardiovascular diseases include obesity, smoking, consumption of alcohol, high blood pressure, advanced age and lack of physical exercise," said Cai.
