We’ve long been told to watch our waistlines. Along with a high body mass index (BMI), excess belly fat is a warning sign of health problems like heart disease and type 2 diabetes. A BMI of over 25 is considered overweight, while 30 or higher is obese.
But should we look for warning signs elsewhere, too? On our arms?
If the circumference of the upper arm (taken halfway between the shoulder and the elbow) is greater than 32 cm (12.5 inches) someone is likely to be obese, and recent studies suggest that having more fat around the arms may mean a higher risk of Alzheimer’s, heart disease, fatty liver disease and even osteoporosis.
In some cases, risks increased even when BMI was healthy.
Like fat stored around the legs, arm fat was previously thought to be largely benign — or at least less harmful than fat stored around the abdomen — which is a sign that someone also has more visceral fat (a more harmful type that’s stored in and around our organs).
Recent studies suggest that having more fat in your arms may mean a higher risk of Alzheimer’s, heart disease, fatty liver disease and even osteoporosis.
However, research published a few weeks ago by scientists at Sichuan University in Chengdu, China, suggests otherwise. The researchers analysed data from 412,000 people in the UK over a nine-year period to identify any links with Alzheimer’s and Parkinson’s diseases.
Volunteers were measured for waist and hip size, arm circumference, fat mass (a measure of total body fat), and muscle mass (the same, but for muscles).
People with excess abdominal fat were 13 percent more likely to develop disease than those with low levels.
Previous research has found that belly fat may be linked to Parkinson’s (where a gradual loss of brain cells leads to tremors, stiffness, slowness of movement and freezing) by altering insulin levels and triggering a complex reaction that leads to a drop in dopamine, the brain chemical that helps regulate movement.
But the new study also found that those with the most arm fat had an 18 percent higher risk of Alzheimer’s or Parkinson’s, and were also more likely to develop heart disease.
In contrast, those with muscular, rather than flaccid, arms were 26 percent less likely to develop either condition.
As a result of their findings, the researchers suggested that a program to reduce fat and build muscle in the arms may be more effective in preventing these problems than general weight loss.
The new study also found that those with the most arm fat had an 18 percent higher risk of Alzheimer’s or Parkinson’s, and were also more likely to develop heart disease.
These are not the only serious conditions that can be linked to arm fat. Research presented at the European Congress of Endocrinology in May showed that measuring arm fat can be used to identify people at risk of spinal fracture due to undiagnosed osteoporosis.
Researchers at the National and Kapodistrian University of Athens studied people aged between 50 and 60 with no history of the disease. They found that those with high levels of visceral fat had poorer quality bones in the spine, putting them at risk of a life-changing fracture.
But the same was true for those who had fat arms, even if they were not obese according to their BMI.
In the study, researchers used calipers, a tool that “pinches” the skin, to measure the fat beneath the skin.
Arm fat is thought to be a marker for hidden visceral fat, which is known to release inflammatory chemicals into the blood that can accelerate bone loss.
The findings could be significant because many people are only diagnosed with osteoporosis after suffering a fracture.
Eva Kassi, professor of endocrinology who led the study, said: “It is surprising that we found that arm fat mass is negatively associated with bone quality. This could mean that arm fat becomes a useful index of spinal bone quality.”
Meanwhile, a study from Wenzhou Medical University in China, published in May in Frontiers In Public Health, found that children aged 12 to 18 with larger arm circumferences were 25 percent more likely to have dangerous levels of fat around the liver, known as nonalcoholic fatty liver disease (NAFLD).
Linked to obesity and poor diet, NAFLD can lead to scarring (cirrhosis), liver failure or cancer.
So should we all measure our arms instead of our waist?
Not yet, says Wasim Hanif, professor of diabetes and endocrinology at University Hospital Birmingham, because upper arm fat is much less “metabolically active” – the type linked to chronic disease.
“The worst type of fat is visceral fat, which is found in the abdomen, because of its association with type 2 diabetes and heart disease,” she says. “If I had to choose between having a big belly or fat arms, I would always choose my arms.”
However, some researchers remain convinced that arm fat is important. Professor Kassi’s team is planning to expand their studies into bone health to see if they can detect younger men and women (aged between 30 and 40) who might be at risk of osteoporosis, based on the levels of fat in their arms.
Those at high risk will be put on exercise programs to burn arm fat in the hope that this will reverse the damage to the bone.
