Key Points:
- Higher dietary niacin correlates with increased muscle mass and grip strength.
- Elevated dietary niacin is associated with lower total body fat.
- Dietary niacin significantly reduces insulin resistance, where cells don’t respond effectively to the blood sugar regulating hormone insulin, to enhance insulin signaling.
Studies have shown that muscle strength drops significantly after the age of 40. Strength loss stems from the reduction of muscle mass which may ultimately lead to frailty, encompassing reduced mobility and troubles performing everyday tasks. Muscle loss during aging leads to impaired sugar (glucose) absorption since muscle is a key site of glucose uptake, and this altered glucose absorption disrupts insulin signaling, precipitating diabetes. Although some evidence shows that niacin improves muscle mass and strength, whether it does so in adults aged 40 and over hadn’t been tested, until now.
For the first time, in a study published in the Journal of Nutrition, Health, and Aging, Liu and colleagues show that dietary niacin supplementation increases muscle mass and strength in adults over age 40. A niacin-infused diet also lowers total body fat. In addition to improving body composition — increased muscle and lowered fat — niacin reduces insulin resistance so that cells respond more effectively to the blood glucose regulating hormone insulin. These findings show a link between increased dietary niacin, boosted muscle mass and strength, lowered body fat, and increased insulin sensitivity.
Increasing Dietary Niacin Improves Muscle Mass, Strength, and Insulin Signaling and Lowers Body Fat
To find whether increased levels of dietary niacin correlate with increased muscle mass and strength, Liu and colleagues analyzed over 3,000 adults above the age of 40 for muscle mass and strength. The researchers surveyed the adults regarding their consumption of dietary sources of niacin and calculated their niacin intakes accordingly. They found that for every 1 mg/kg of daily niacin intake, appendicular lean mass — the amount of lean muscle in the legs and arms — significantly increased by 0.025 kg per kg of body weight. Using a test of grip strength, the researchers also found that for every 1 mg/kg of daily niacin, grip strength significantly increased 0.275 kg/kg of body weight. Cumulatively, these findings show that increased dietary niacin correlates with more muscle mass and greater strength.
Liu and colleagues then assessed 3,279 adults over age 40 to find whether increasing dietary niacin reduces total body fat. Interestingly, they found that for every 1 mg/kg of dietary niacin consumed per day, total body fat significantly decreased 0.061 kg/kg of body weight. These results show that increasing dietary niacin reduces total body fat, thus improving body composition.
Since increased muscle mass improves cellular glucose uptake and glucose-regulating hormone insulin signaling, Liu and colleagues tested how increasing niacin affects insulin resistance. They tested 9,189 adults over the age of 40, some with diabetes and others that were non-diabetic. For both groups of participants, increased dietary niacin significantly reduced insulin resistance, although the effect was greater for adults with diabetes. These findings show that increasing dietary niacin is associated with insulin signaling improvements, which facilitates improved metabolism.
“Niacin intake at dietary doses in people aged 40 years and older is associated with increased skeletal muscle mass and strength and loss of body fat, and it may improve glucose homeostasis,” said Liu and colleagues.
Supplementing with NAD+ Precursors Like NMN May Also Improve Muscle and Insulin Signaling
The study shows that increasing dietary niacin up to 1.5 mg/kg of body weight correlates with significantly increased muscle mass and strength, reduced fat, and improved insulin signaling. An average adult weighing 170 pounds also weighs 77.27 kg. Thus, consuming 1.5 mg/kg would equal a daily niacin intake of 115.9 mg. Obtaining higher dietary amounts of niacin comes from consuming milk, meat, fish, chicken, and turkey, all high in niacin. Niacin supplements are also available in 500 mg or 1000 mg capsules for daily consumption. Prescription niacin ranges from 500 mg to 2000 mg per day, so dietary amounts of 115.9 mg per day to obtain these benefits falls well below the supplement and prescription doses.
The study is based on surveys of participants’ daily niacin intake, which may contain inaccuracies, a key limitation. Moreover, none of the parameters measured —muscle mass, strength, total body fat, and insulin resistance — showed a plateauing effect where niacin’s benefits waned at higher doses. For this reason, future studies should also test whether even higher niacin doses confer greater benefits toward muscle mass, strength, reduced body fat, and improved insulin signaling. Importantly, the study only showed an association between increased dietary niacin and its benefits, so future studies should determine whether increased niacin causes improved muscle mass and strength and insulin signaling along with lower body fat. Other studies suggest that the NAD+ precursor NMN improves physical functioning in aged adults, which likely comes from enhanced muscle mass and strength. More research is needed to find whether niacin’s effects on muscle mass, strength, lowered body fat, and improved insulin signaling come from other NAD+ precursors.
Comments