Previous research has already linked a healthy diet high in fruit and vegetables to “skin yellowness” — which the researchers say is an indicator of health — as fruit and veggies are packed with antioxidant coloured pigments called carotenoids, such as orange carotene from carrots and red lycopene from tomatoes. These coloured pigments then accumulate in the skin, giving it a yellow tone which can indicate good health as it suggests that a person’s body has enough antioxidants and low levels of oxidative toxins.
However, for the new study, led by the University of St Andrews, the researchers wanted to look at the link between skin yellowness and exercise. To do this, the team recruited 134 university students of various ethnicities, and measured their skin colour using a spectrophotometer, which records illumination and the rainbow of colours reflected from the skin. The participants also had their heart rate measured while walking and running on a treadmill to assess their fitness levels and had their body fat levels recorded.
The findings, published in the journal Frontiers in Psychology, showed that both a high level of fitness and low body fat were associated with a higher skin yellowness, which makes the skin look healthier and more attractive.
The team say that the “yellower” skin was not due to a suntan or even diet. Instead, they believe that exercise could boost the body’s own antioxidant systems, and so, instead of needing to use up the carotenoid pigments which we ingest from our diet, they are free to accumulate in the skin, giving us a yellow tone.
The researchers then looked at whether experiencing a change in health would also result in a change in skin appearance.
After following 59 students who were members of sports clubs, the researchers found that an increase in fitness or losing body fat were both linked with an increase in skin yellowness. On the other hand, an increase in stress and a not getting enough sleep were both associated with a reduction in skin yellowness.
Once again, the researchers say changes in skin colour change were not due to suntan or from training outdoors.
The findings now suggest that in addition to eating plenty of fruit and vegetables, other healthy lifestyle factors such as exercising, losing excess body fat, reducing stress and getting enough sleep could all boost skin colour. As skin colour is also linked to attractiveness, they added that this could help motivate people to follow a healthier lifestyle.
Lead scientist for the study, Professor David Perrett, adds: “We were surprised to find that the skin colour changes accompanying change in health occurred quite quickly and within eight weeks. This means that any effort to improve lifestyle will benefit appearance within a relatively short time.”
Plant protein and dairy could improve heart health
The findings from two preliminary studies that were presented at the American Heart Association’s “Epidemiology and Prevention — Lifestyle and Cardiometabolic Health Scientific Sessions 2020” have suggested that eating less red meat and more protein from plant and dairy sources could improve heart health and lower an individual’s risk of death.
The first study, carried out by researchers at Harvard T.H. Chan School of Public Health in Boston, US, looked at more than 37,000 Americans with an average age of 50.
After estimating the amount of plant protein compared to animal protein in the participants’ diets and comparing that to their risk of dying, the researchers found that those who ate the most plant protein were 27% less likely to die of any cause and 29% less likely to die of coronary heart disease, compared to those who ate the least amount of plant protein.
They also found that if participants replaced 5% of their daily calories from animal protein with the equivalent number of calories of plant protein, they could lower their risk of dying of any cause, including dying from coronary heart disease, by nearly 50%.
In addition, replacing just 2% of daily calories from processed meat protein with an equivalent number of calories from plant protein was associated with a 32% lower risk of death.
In the second study, also by Harvard T.H. Chan School of Public Health, researchers followed 43,259 male participants for up to 26 years and found that swapping one serving per day of red meat or processed red meat with plant foods such as nuts, legumes, and whole grains, or with dairy, was associated with up to a 47% lower risk of having coronary heart disease.
In addition, replacing one serving of any type of red meat each day with an equivalent amount of nuts, and without upping the number of calories consumed, was linked to a 17% lower risk of dying of a heart attack, while replacing one serving of red meat with whole grains resulted in a 48% lower risk of dying of heart attack.
“It isn’t enough just to avoid red meat — it’s also about what you choose to eat in place of red meat,” adds lead author of the first study, Zhilei Shan. “Healthy plant proteins like nuts, legumes and whole grains contain more than just protein — they include other beneficial nutrients such as healthy fats, antioxidant vitamins, minerals and phytochemicals (compounds derived from plants), which have been associated with lower risk of chronic diseases such as diabetes, cardiovascular disease and some cancers.”
