A new study from the University of East Anglia (UEA) has revealed that older people who consume more foods that are rich with vitamin C have the best skeletal muscle mass.
Generally, as we get older, our muscle mass, strength and power to move, gradually declines, often leading to condition called sarcopenia. "People over 50 lose up to one per cent of their skeletal muscle mass each year, and this loss is thought to affect more than 50 million people worldwide. It's a big problem, because it can lead to frailty and other poor outcomes such as sarcopenia, physical disability, type-2 diabetes, reduced quality of life and death,” said lead researcher Prof Ailsa Welch, from UEA's Norwich Medical School.
Currently, there are limited solutions for treating sarcopenia, so early intervention, before symptoms become too severe, is preferable. Most research, until now, has focused on the effect of increasing protein intake to prevent or treat sarcopenia.
However, this new study, published in The Journal of Nutrition, attempted to investigate the importance of dietary vitamin with loss of skeletal muscle mass and function in middle and older age. The study concluded that the more dietary vitamin C middle-aged and older adults consume, the greater their skeletal muscle mass appears to be.
Vitamin C is abundantly found in citrus fruits, berries and vegetables and people who do not consume enough of these in their diet are at risk of vitamin C deficiency which, in turn, causes weakness, tiredness and fragile bones. In extreme cases, vitamin C deficiency may lead to scurvy.
Around two-thirds of our body’s total vitamin C is found in skeletal muscle and is used for making carnitine, a substance crucial in providing energy for muscles to function, and collagen which is an essential structural component of muscle. Vitamin C is also a strong antioxidant that can help to counteract free radical molecules which increase with age. Unopposed, these free radical molecules can contribute to destruction of muscle cells.
For this study, researchers looked at data from over 13,000 men and women aged 42-82 years who were participants in the European Prospective Investigation into Cancer and Nutrition (EPIC) Norfolk study. They used biological impedance analysis, which sends small electrical signals through the body to calculate water and fat percentage, thus estimating the proportion of skeletal muscle in the body.
Participants were requested to maintain a diary of everything they ate and drank over a period of seven days so that the research team could accurately calculate their intake of dietary vitamin C. Vitamin C levels were also measured directly in their blood, providing results less susceptible to potential error in reporting diet. Participants were then grouped according to their intake of vitamin C, ranging from low to high.
Analysis of the collated data took into consideration other important factors, including participant’s physical activity, protein and energy intake, which might also have effects on skeletal muscle mass.
They found that participants who had consumed the highest amount of vitamin C in their diet had the greatest muscle mass. The results indicated the largest difference in women who had consumed highest category of vitamin C, showing muscle mass 3% higher than those in the lowest category. For participants under as well as over 65, vitamin C was seen to be an important factor in maintaining better skeletal mass. These findings were also supported by the fact that those with sufficient levels of vitamin C in their blood had greater muscle mass than those in the insufficient category.
"We found that nearly 60 per cent of men and 50 per cent of women participants were not consuming as much Vitamin C as they should, according to the European Food Safety Agency recommendations. We're not talking about people needing mega-doses. Eating a citrus fruit, such as an orange, each day and having a vegetable side to a meal will be sufficient for most people,” said Dr Richard Hayhoe, from UEA's Norwich Medical School.
The results from this study build on the concept that optimal nutrition may help reduce the decline in muscle. This provides further emphasis and encouragement for people of all ages to follow the healthy eating guidelines and consume a wider variety of fruits and vegetables every day.