Calorie restrictive diets often emphasize nutritive sources, like cherries. Photo source.
Calorie restrictive (CR) diets have been proclaimed as an anti-aging source. According to Wikipedia, in human subjects, calorie restriction has been shown to lower cholesterol, blood pressure, and resting blood glucose levels. The diet has also been associated with increased lifespan in primates, rats, mice, spiders, Drosophila, C. elegans and rotifers. However, what does current scientific research say about potential benefits of a calorie restrictive diet for the skin?
Have there been any substantiated benefits of calorie restrictive diets and the skin?
Based on various scientific studies, calorie restriction may help the skin in four potential ways: decreasing contact dermatitis, prolonging the life of cells by upregulating sirtuin gene (SIRT1) levels, possibly preserving cellular DNA by decreasing free radical formation, and potentially preserving the softened, youthful state of collagen by decreasing the formation of advanced glycation endproduct glucosepane. More on each of these topics is below.
It was once believed that CR promoted levels of DHEA, a steroid prohormone that acts as a potent antioxidant in the skin. However, a 2004 study by Urbanski et. al. found that, while a calorie restrictive diet results in increased levels of DHEA in primates before puberty, CR does not affect DHEA levels in primates after puberty.
Do calorie restrictive diets really decrease contact dermatitis?
In the journal Toxicologic Pathology, researchers in 2001 found mice fasting for 48 hours had a lower level of allergic contact dermatitis when 2,4-dinitrofluorobenzene (DNFB) was applied to the abdomen than mice who fasted for only 24 hours. The researchers believe that the reason for the lowered occurrence of allergic contact dermatitis is the fact that fasting alters various hormonal and immune conditions, resulting in a delayed immune response and, hence, a lowered allergic reaction.
How do calorie restrictive diets affect sirtuin levels?
A study published in Science magazine in 2004 demonstrated that CR diets in mammals turn on SIRT1 gene expression. Sirtuins are associated with prolonging the life of cells by turning off unnecessary gene expression. In the skin, the company Avon has demonstrated in research for their Avon Anew Ultimate Age Repair Elixir Serum and Night Cream that sirtuins in the cream can prolong the life of fibroblasts (collagen-producing cells in the skin) by turning off unnecessary gene expression. The idea behind sirtuins in skin care is to prolong the life of the fibroblasts, which aren’t expending more energy than they need to on unnecessary tasks. Therefore, by following a CR diet, you are increasing levels of sirtuins in your skin.
Does niacinamide hinder sirtuin activity?
Unfortunately, yes, sirtuins are inhibited by niacinamide, as demonstrated by a 2005 study by Avalos et. al. Niacinamide, proclaimed a “favorite skin care ingredient” by renowned cosmetic dermatologist Dr. Leslie Baumann, demonstrates many benefits in various independent research studies, as it has been shown to reduces fine lines and wrinkles, hyperpigmented spots, red blotchiness, and skin sallowness (yellowing), and increases elasticity. However your attempts to increase levels of sirtuins in your skin with a CR diet may be mostly futile if you use a moisturizer with niacinamide. Yet, given that topically niacinamide has so many documented effects for the skin, until further research is done, it seems to be a question of whether you want the effects of sirtuins or niacinamide more!
Does CR lower free radical production?
According to a 2001 study by Gredilla et. al., a 40% calorie restrictive diet was shown to decrease the level of free radical superoxide (an oxygen free radical) per unit electron flow in the respiratory chain. While studies at MIT have demonstrated that oxygen free radicals do not contribute to a shortened lifespan, another study has demonstrated that oxygen free radicals can damage the DNA of cultured skin cells. As such, using a CR diet to reduce oxygen free radicals may not expand longevity, but it reduce levels of oxygen free radical-induced DNA damage in the skin.
How does CR prevent collagen from hardening?
According to DeGrey, advanced glycation endproducts (appropriate acronym: AGE) play an important role in the aging of all of the cells of your body, including within the skin. AGEs come from the processing of blood sugar via the Maillard pathway (see here for more information). The advanced glycation endproduct called glucosepane is believed to be responsible for the toughened, hardened, aged state of collagen.
By using CR, you reduce blood sugar levels. By reducing blood sugar levels, you reduce the amount of sugars going into the Maillard pathway. As basic chemistry entails “less in equals less out,” by feeding less sugar into the Maillard pathway, it makes sense that less advanced glycation endproducts should result after the pathway.
However, sugar avoidance (like the Atkins diet) is not the solution. In a 2005 study by Beisswenger, patients were put on the Atkins diet, and it was found that the rate of AGE formation was actually doubled. (The patients were proven to be following the diet and appropriately “in ketosis” by the presence of ketones in their urine.) It seems that ketosis doubles the presence of methylglyoxal in the body, which react with Amadori products, forming twice the AGE products that would normally be present. Therefore, if CR results in ketosis, it will actually increase AGE formation.
How much do I eat on a calorie restrictive diet?
According to the Calorie Restriction Society, achieving 10 – 25% below your current set point weight is considered reasonable. The definition for “set point” is somewhat vague: “…that weight toward which one naturally drifts,” according to founder Roy Walford. The society has further refined that measurement to suggest that a safe CR weight to strive for is “generally considered to be your lean set-point weight: your weight during late teens to mid-20s, providing you were not overweight (e.g. obese) or underweight (e.g. anorexic) in your teenage years.”
Further, in an article from New York magazine, 30 percent of daily calories must come from protein, 30 percent from fat, and the remaining 40 percent from carbohydrates. Due to such low calories, according to Wikipedia, sufficient quantities of vitamins, minerals and other important nutrients must be eaten, and one fan of CR with a blog states that ensuring adequate nutrition through careful tracking of one’s diet is crucial: “Make sure you supplement any deficiencies. You need to track your diet with a tool to know what these are. This is not optional!” It is also advisable to talk to your doctor before beginning any sort of calorie restrictive diet.
Is a CR diet the same as CRON, CRAN, or CRL?
According to Wikipedia, to emphasize the difference between CR and mere “FR” (food restriction), CR is often referred to by other names such as CRON or CRAN (calorie restriction with optimal/adequate nutrition), or the “high-low diet” (high in all nutrients aside from calories, in which it is “low”), or the “longevity diet” (also abbreviated CRL).
In summary, based on current research, is a CR diet good for my skin?
Based on current scientific research studies, it has been established that a CR diet may reduce skin’s levels of oxygen free radicals and allergic contact dermatitis. In addition, if the CR diet does not result in ketosis (a state associated with starvation), it may prevent advanced glycation endproduct formation.
However, if the CR diet results in ketosis (a state associated with starvation), your skin will age faster.
This is because advanced glycation endproduct formation will increase, based on the 2005 study by Beisswenger.
Further, skin’s levels of sirtuins will increase, which may be beneficial in the long run, but only if they are not inhibited by moisturizers containing niacinamide, which is otherwise a spectacular skin care ingredient.
At this time, based on what I have read, I personally am following a healthy, balanced, “everything in moderation” diet, with a few extra potent antioxidant sources (green tea, vegetables) and slow-cooked meals (which form less advanced glycation endproducts). More on food that is good for your skin here!
Overall, if you are considering a calorie restrictive diet or any other kind of diet, consult your physician!