The end of fasting4 min read . Updated: 29 Apr 2016, 04:35 AM IST
Fasting before a lipid profile is standard medical practice. According to a latest recommendation, it may be time to stop it
You are fasting, sir?" My family—like so many millions across India with cardiovascular vulnerabilities—is familiar with the regular, and irksome, testing routine for cholesterol and triglycerides. Stop eating by 7pm and 8pm and remember not to have anything, save a few sips of water, until you get to the testing centre the next morning, within eight to 10 hours. If your cholesterol is being tested, you need to return some hours later, after breakfast, to provide another blood sample.
None of this may be necessary, according to the first international recommendation of its kind released on Wednesday through a paper in the European Heart Journal. Your stomach does not need to be empty before your cholesterol and triglycerides—both markers for a variety of cardiovascular ailments—are tested as part of your lipid profile because such tests add no clinical value, according to new research conducted on 300,000 people across Denmark, Canada and the US. The recommendations come through a joint statement from 21 medical experts from Europe, Australia and the US.
Denmark ceased fasting samples of cholesterol in 2009, the only country to do so. The Nordic country uses random, non-fasting tests for cholesterol at any time of the day and allows you to eat what you want. If the trend set in Denmark proliferates across the world, it would increase testing to reduce the risk of strokes and heart attacks, now a leading cause of death globally. As a result of a genetic predisposition and sedentary lifestyles, Indians suffer among the world’s greatest cardiovascular risk.
Random, no-fasting testing would encourage younger people, especially those who work uncertain hours, to get checked. This is important in India because those at risk of cardiovascular diseases are now younger than ever. It would help the elderly, especially those with diabetes, to avoid fasting, which could weaken them. Diabetes patients are at risk of hypoglycemia—plunging blood-sugar levels that cause blackouts or worse—if they fast.
The idea that fasting isn’t necessary for lipid testing is comparatively new for the world outside Denmark. A 2012 analysis in Archives of Internal Medicine, a US medical journal, said routine lipid testing was “largely unnecessary", although the American College of Cardiology and the American Heart Association continued to recommend blood tests after fasting, as do medical associations across the world, including India.
The conventional rationale for fasting before a lipid test is this: food determines the levels of sugar and cholesterol in your blood, skewing measurements of your body’s ability to handle them. Fasting allows a determination of what medical experts call the “bottom line", or the lowest possible sugar and cholesterol levels. If these levels are high after fasting, something is likely to be wrong.
This explanation was a result of a medical consensus between experts, but repeated testing has revealed problems with this hypothesis.
In 2014, an analysis of US national health data found no significant difference between fasting and non-fasting LDL (low-density lipoprotein, commonly called “bad" cholesterol) cholesterol levels in predicting cardiovascular mortality, according to a paper in the journal Circulation, written by New York University associate professor Sripal Bangalore and his colleagues.
People do not normally fast, so asking them to fast is not natural, said Bangalore during a 2014 interview with MedPage Today, a medical-information service. “To me it’s like studying for an exam to do well on a test," he said. “It is an artificial situation."
This situation—fasting—can create additional risks. Patients with more than one hypoglycemic episode were at higher risk of death than those who had never experienced one, according to two major US studies that analysed the lowering of glucose levels. Other tests reported an increase in LDL levels after 12 to 24 hours of fasting. The Circulation study found no difference in outcomes between fasting and non-fasting triglycerides, total cholesterol and LDL.
Other large-scale studies found only statistically insignificant variations between fasting and non-fasting samples. This bears some explanation. For instance, variations of less than 20% for triglycerides may appear substantial, but the increase of non-fasting levels over fasting was roughly 0.3 millimoles per litre (mmol/L), the standard unit for measuring glucose in blood. Just as weight is measured in grams, molecular counts are measured in moles. A mole is 6.022*10^23 molecules, and variations in total or LDL cholesterols are considered negligible below 1 mmol/L.
In other words, there is little difference between fasting and non-fasting lipid profiles, and, so, the time may be here for us in India—home to a lucrative medical diagnostic industry—to re-evaluate the dogma of fasting before lipid tests. This is, perhaps, not something that should be done before large-scale tests in India. Given the effort and money currently spent on lipid testing, it is time to start these studies.
Samar Halarnkar is editor of Indiaspend.org, a data-driven, public-interest journalism, non-profit organization. He also writes the column Our Daily Bread in Mint Lounge.
Comments are welcome at firstname.lastname@example.org. To read Samar Halarnkar’s previous columns, go to www.livemint.com/frontiermail