Sharp swings in blood sugar over short periods may accelerate skin aging, medical experts say, suggesting that blood glucose management matters beyond diabetes prevention.
Woo Chang-yun, an endocrinologist and clinic director, explained the effect of glucose fluctuations on skin collagen, saying that "when blood sugar swings, collagen gets coated with sugar," according to medical sources on the 2nd.
Woo added that "wide swings in blood sugar accelerate the breakdown of collagen." Each time glucose rises and falls sharply, glycation occurs in the body, and repeated cycles impair the function of collagen and elastin, the proteins that keep skin firm, potentially advancing the aging process.
Glycation is a reaction in which glucose in the blood binds to proteins and lipids without the help of enzymes, producing advanced glycation end products (AGEs). Collagen and elastin, the structural proteins of the skin's dermal layer, are primary targets of glycation, and glycated collagen loses strength and elasticity, leading to sagging and wrinkles, researchers say.
Glycation is also cited as a factor that increases inflammation and oxidative stress while triggering pigmentation that leaves skin tone uneven.
Women are at a relative disadvantage when it comes to these fluctuations, Woo said. "Women have less muscle mass than men, so they have fewer sponges to soak up blood sugar," he said. "They also tend to eat more sweets, so their blood sugar swings more widely than men's."
Normal-weight obesity and visceral fat obesity, in which body fat concentrates around the abdomen despite low muscle mass, are also more common in women. The population that needs to manage blood sugar is already broad. According to the Korean Diabetes Association's Diabetes Fact Sheet 2024, about 5.33 million Korean adults aged 30 and over have diabetes, and the figure reaches about 14 million when prediabetes is included. Some 37% of men in their 30s were classified as prediabetic, as were 3 million young adults, or one-fifth of that age group.
Adjusting the diet is the first step in narrowing those swings. "Eating multigrain rice cuts peak post-meal blood sugar by more than 20%," Woo said. "That also reduces glycation of skin collagen, which can slow wrinkles and aging." There are digestive benefits as well.
"Multigrain rice is the easiest way to get dietary fiber," he said, "because it contains both insoluble and soluble fiber, such as the bran in brown rice and the beta-glucan in oats." Soluble fiber helps control post-meal blood sugar and lower plasma cholesterol, while insoluble fiber, abundant in whole grains and vegetables, helps regulate bowel movement.
Actual intake in Korea, however, falls short of guidelines. Korea's dietary reference intakes set adequate fiber intake for adults at 25 grams for men and 20 grams for women, but consumption remains below those levels. After eating multigrain rice, drinking plenty of water is recommended so that the larger volume of stool passes smoothly.
