Our project was on a small scale, but Jalan felt it could yield clues as to the effects of short-term abstinence. On 5 October, 14 members of the New Scientist staff – all of whom consider themselves to be “normal” drinkers – went to the Royal Free Hospital in London. We answered questionnaires about our health and drinking habits, then had ultrasound scans to measure the amount of fat on the liver. Finally, we gave blood samples, used to analyse levels of metabolic chemicals linked with the liver and overall health.
For the next five weeks, 10 of us drank no alcohol while four continued as normal. On 9 November, we returned to the hospital to repeat the tests.
“You’re going to be very excited,” said Jalan, when the results were in.
First off, he revealed that there had been no significant changes in any of the parameters measured for the four people who didn’t give up alcohol.
But the changes were dramatic and consistent across all 10 abstainers (see charts).
Liver fat fell on average by 15 per cent, and by almost 20 per cent in some individuals. Jalan says this is highly significant, because fat accumulation on the liver is a known prelude to liver damage. It can cause inflammation, resulting in liver disease. “This transition is the harbinger first for temporary scarring called fibrosis and ultimately a non-reversible type of scarring that destroys liver structure, called cirrhosis,” says Jalan. Although our livers were all judged to be generally healthy, the fat reductions would almost certainly help to retard liver deterioration, he says.
Then came another surprise. The blood glucose levels of the abstainers dropped by 23 per cent on average, from 5.1 to 4.3 millimoles per litre. The normal range for blood glucose is between 3.9 and 5.6 mmol/l. “I was staggered,” says Kevin Moore, consultant in liver health services at UCLMS. “I don’t think anyone has ever observed that before.”
Glucose was measured using a fasting blood glucose test taken after participants had refrained from eating or drinking anything but water for 8 hours. This stimulates production of the hormone glucagon, which releases glucose from body stores into the blood. In a healthy person, a rise in glucose triggers the production of insulin, which tells certain cells to take up glucose from the blood to maintain a safe blood sugar level.
Type 2 diabetes results when cells no longer respond to insulin, leading to high blood sugar. A drop in circulating glucose in our tests could mean that our bodies had become more sensitive to insulin, removing more glucose from the blood – a sign of improved blood sugar control. We also lost weight, by 1.5 kilograms on average.
Total blood cholesterol, a risk factor for heart disease, dropped by almost 5 per cent, from 4.6 to 4.4 mmol/l. A healthy amount is considered anything below 5.2 mmol/l. “Basically, you’re getting improved glucose and cholesterol management,” says Moore.
The benefits weren’t just physical. Ratings of sleep quality on a scale from 1 to 5 rose by just over 10 per cent, improving from 3.9 to 4.3. Ratings of how well we could concentrate soared 18 per cent from 3.8 to 4.5. “It represents a significant effect on quality of life and work performance,” says Jalan, although he acknowledges that self-reported experiences are open to bias.
The only negative was that people reported less social contact.
Our experiment gives no indication of how long the improvements persist. “Whether it’s 15 days or six months, we don’t know,” says Jalan. However, it lays the ground for larger studies, he says.
