Quick Studies: A snapshot of the latest research on diet, exercise, and more

An Apple a Day...

Is apple juice or purée equal to an apple? Scientists had 18 adults consume, on three different days, 178 calories’ worth of apple slices, apple purée, or apple juice. The purée included the peel, so it had about as much fiber as the slices (7 grams). The juice had less (2 grams).

The participants’ stomachs took longer to become half empty after they ate the apple slices (65 minutes) than after the purée or apple juice (about 40 minutes). They also felt the most full after eating the apple slices and the least full after drinking the juice.

What to do: Build your diet around unprocessed whole foods. Don’t assume that high-fiber processed bars or shakes will keep you feeling full.

J. Nutr. 2020. doi:10.1093/jn/nxaa191.

Have a “Snack”

We’re talking exercise, not food. When 11 adults with overweight or obesity spent 9 hours taking an hourly stair-climbing “snack”—which meant briskly climbing 55 steps—their blood insulin levels were 17 percent lower than when they spent 9 hours sitting. Each “snack” took 20 to 60 seconds.

What to do: Try taking exercise “snacks.” High insulin levels are a risk factor for type 2 diabetes and cardiovascular disease.

Med. Sci. Sports Exerc. 2020. doi:10.1249/MSS.0000000000002431.

Clues to Pancreatic Cancer

Unplanned weight loss and diabetes may be signs of pancreatic cancer.

Scientists tracked some 160,000 adults for roughly 30 years. Compared to those without diabetes, those who had been diagnosed with the disease more than four years earlier had double the risk of pancreatic cancer, while those with a recent diagnosis had triple the risk. (That said, their risk over four years was still low—only about 3 cancers per 1,000 people.)

People who had recently lost more than 8 pounds had a 69 percent higher risk of pancreatic cancer than those with no weight loss. And people who had lost at least 8 pounds and had a recent diabetes diagnosis had six times the risk of those with neither. (Their four-year risk was 7 cancers per 1,000 people.)

What to do: Though more research is needed, check with your doctor if you’ve lost weight without trying.

JAMA Oncol. 2020. doi:10.1001/jamaoncol.2020.2948.

Vitamin D & Covid-19

Could low blood levels of vitamin D raise the risk of Covid-19?

Researchers studied 489 people who had had their vitamin D levels tested within a year (on average, five months) before being tested for Covid-19.

Roughly 12 percent of those with “adequate” vitamin D levels (at least 20 ng/mL)—versus 22 percent of those with lower levels—tested positive for Covid-19.

What to do: It’s impossible to know if vitamin D can prevent—or curb—a Covid infection without a clinical trial that randomly assigns people to take either vitamin D or a placebo. (Fortunately, at least 30 trials are underway.) Covid or not, it’s worth taking the RDA for vitamin D (600 IU a day up to age 70 and 800 IU a day if you’re older) to avoid insufficient levels.

JAMA Netw. Open 2020. doi:10.1001/jamanetworkopen.2020.19722.