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HERE COMES THE SUN!

With the sun and temperatures finally above freezing, it’s a relief to be able to get outside without layers to insulate from the cold. Sun exposure benefits us by allowing our skin to produce vitamin D. This occurs fairly rapidly: six days of casual sunlight exposure without sunscreen allows Caucasian skin to produce enough vitamin D to last 49 days; another study shows exposure of the hands and arms, face, and legs to sunlight for 25 % of the time needed to turn red, 2-3 days a week, produces enough. Or, an untanned Caucasian wearing a swimsuit can make 10 days-worth after 11 minutes of peak July summer sun in Boston; for Asian Indians this would take about 30 minutes, and for dark African Americans it could require 120 minutes. Despite these small doses of sun, the current recommendation is to take a vitamin D supplement and protect ourselves from any sun exposure because it causes skin cancer and accelerates skin aging. Tanning beds also produce dangerous UVA and UVB radiation, and age the skin the same as the sun. Tanning bed use is not recommended.

Protection from sun can be physical, in the form of clothing and hats with 4 inch brims, and can be augmented by some form of sunscreen lotion or cream.   Zinc oxide and titanium dioxide protect from UVA (1 and 2) as well as UVB; chemical sunscreens use a combination of organic “filters” (chemicals) such as octinoxate (for UVB radiation) and oxybenzone (UVA). These chemicals change the harmful rays into a small amount of heat. Plain zinc oxide is what mountain climbers traditionally use; applied to the skin in a cream that isn’t absorbed, it is a physical block to radiation. Nanotechnology now allows zinc oxide and titanium oxide to be used in cosmetically acceptable lotions that don’t show after application. Depending on skin type,   people need to use a product with at least a sun protective factor (SPF) of 15, 30+ for those who have more sensitive skin. The best protection is obtained by applying lotion 15 to 30 minutes before sun exposure to allow the formation of a film on the skin;   reapplication is needed after swimming,   sweating, or every two hours. The term “waterproof” is no longer allowed. Even water resistant formulas need to be reapplied after time spent in the water: “water resistant” lotions need reapplication after 40 minutes, “very water resistant” after 80 minutes. With Fairbanks’ adjusted time zone, the sun’s rays are strongest between noon and 6 pm.

There are many products on the market that contain various plant additives purported to protect the skin from sun damage and aging. There is evidence of modest protective benefit for a topical (used on the skin, not eaten) combination of vitamins C, E, and melatonin, but only when applied before sun exposure.   Vitamin C is contained in rose hips, acerola, and other fruit extracts and can have antioxidant effects. Some evidence shows reduction of fine wrinkles with topical use of vitamin C. Topical niacin and niacinamide help acne, and as antioxidants may also help aging skin. High oral doses of vitamins C and E may provide some benefit to skin, however, there are other risks and side effects, so this is not recommended. One oral preparation contains a toxic amount of vitamin A; as usual, read labels. Green tea, acai, vitamins E and A in topical preparations are touted for skin protection and reduction of wrinkles, but no reliable evidence exists to support these claims. Smokers who take 20 mg or more of beta carotene (related to vitamin A) may actually have an increased risk of lung or prostate cancer.

Dry skin can make wrinkles more pronounced; moisturizers can temporarily puff up the skin and reduce wrinkles. Occlusive moisturizers like avocado, emu or mineral oil, shea and cocoa butter, petrolatum and lanolin work well. Humectants, including glycerin, propylene glycol, hyaluronic acid, lecithin, and others are not recommended here as they can lead to dry, cracked skin In the dry climate of Fairbanks.  

Exfoliators peel away the top layers of skin and may decrease fine wrinkles. Exfoliators can be mechanical, as with sugar or salt scrubs in an oil base, or chemical. Alpha hydroxy acids are chemical exfoliants. High concentrations of these acids, including glycolic, lactic and citric acids, and pyruvic acid, are used in dermatologists’ offices. Lower doses may be used by trained cosmetologists. Much lower doses are available in over-the-counter products. As hydroxy acids are natural fruit acids, fruit and sugarcane extracts are touted to work the same way as straight alpha hydroxy acids, but there is no evidence to support these claims. Likewise, papaya and papain are advertised to decrease wrinkles without evidence of efficacy.

Aloe vera gel, widely used for all sorts of skin conditions, likely does help damaged skin, though the evidence, surprisingly, is limited. There is no reliable evidence that it decreases wrinkles. “Gel” contains only the center of the leaf and is usually different from “juice”, which includes the cells covering the leaf. These outer cells make the “latex”, or “sap”, which contains anthroquinones, substances that are irritating to mucus membranes.

Kinetin is a plant growth hormone marketed to reduce wrinkles; no reliable evidence supports this claim.  

Preliminary studies on some substances are promising but not reliable enough yet to recommend. These include a Central American fern, Polypodium leucotomos, and DMAE (deanol or dimethylaminoethanol, a precursor to the amino acid choline).

Coenzyme Q-10, acetyl-L-carnitine, resveratrol, grape seed extract and many other natural products that may offer benefit for other conditions are often included in skin care products; so far there is no proof of wrinkle reduction from oral or topical use of these.

A few people have various types of skin reactions to organic sunscreens, but these are rare now that PABA is seldom used. However, plant products are more likely to trigger irritation or allergy. Of particular concern is avocado, more likely an issue for people with latex sensitivity.   While alpha hydroxy acids can help reduce wrinkles, they seem to increase sensitivity to the sun, potentially increasing skin damage. If you use products containing these acids, always wear sunscreen with an spf of at least 15, avoid sun exposure, and wear broad-brimmed hats and cover arms and legs with clothing.

REFERENCES

Natural Medicines Database, accessed 4/23/2012

UpToDate, accessed 4/30/2013

The practitioners at the health center have become aware of some students taking various supplements for anxiety. One of these is kava, a plant traditionally used by Pacific Islanders. There is some evidence that kava has mild antianxiety activity; however, it has been connected to liver failure even in standard doses for short durations. It has been banned in Switzerland, Germany and Canada, countries that traditionally use herbs extensively. There is speculation that liver damage occurs in people who more slowly metabolize certain compounds; currently there is no lab test to detect this.  

Another potentially toxic compound is 5-HTP (5-hydroxyltryptophan). This is a substance formed in humans from the amino acid L-tryptophan; it is a precursor to the neurotransmitter serotonin. Serotonin is low in many people with depression, insomnia, obesity, headaches and other conditions, and 5-HTP does seem to help. However, it (and l-tryptophan, too) has been linked to the initially asymptomatic eosinophilia myalgia syndrome which can cause irreversible damage and severe muscle pain. Some, but not all cases of this syndrome have been linked to impurities present in minute quantities; toxicity from it, too, may be caused by genetic susceptibility.   It is often produced from an African plant, Griffonia simplicifolia.

GABA is the primary inhibitory neurotransmitter in the human brain. It is used for anxiety, ADHD, increasing lean muscle mass, and several other conditions. In the 1990s it was studied in single doses of several grams, which seem to produce minimal benefits but can cause elevated blood pressure, unpleasant mood, and could have unpredictable effects on growth hormone. There are no reports of studies of smaller doses, use longer than 4 days, nor more recent studies referenced in my sources.

Theanine is the major amino acid found in green tea, historically used for its relaxing and anti-anxiety effects. Interestingly, one report indicates very small doses of theanine without caffeine are excitatory in rats, with larger doses inhibiting the stimulation of caffeine. One dose used is 200 mg daily; at a concentration in green tea of 1-3 percent, the average tea drinker would get a significantly lower dose, perhaps 20 mg daily. Although no adverse reactions have been reported from consumption of theanine, no large scale studies have been done on humans at doses higher than that obtained by drinking tea.   Another column in this series addressed green tea benefits.

As reported in Scientific   American Mind in March, 2013, a new drug is being researched for those who want to stop their drug addiction. N-acetyl cysteine(NAC) is a substance naturally found in human cells. It has been used for years for many varied situations, including as an antidote to acetaminophen poisoning and to loosen thick mucus in people with cystic fibrosis. It is rapidly absorbed into the body, but can cause nausea and other GI symptoms, worsen asthma, and even cause strong allergic reactions. However, a study last August, published in the American Journal of Psychiatry, demonstrated decreased consumption of marijuana in teenage users, and a 2009 study showed decreased compulsive hair pulling after 9 weeks of treatment. Another study looked at cocaine use over three days of NAC administration, and found users reported half as strong cravings. It seems likely that a combination of cognitive-behavioral therapy with long-term NAC will help significantly larger numbers of people to follow through on their desire to stop at least nicotine, cocaine, methamphetamine, marijuana, and likely alcohol use, and probably other drugs. The 2009 study used 1200-2400 mg daily over 12 weeks. More studies are proceeding.

Be sure to check with your medical provider if you take any prescription medications and plan to take any of these substances; there can significant interactions.

The uses of valerian and rhodiola (for anxiety), and SAMe (for depression) were addressed in previous columns. Saint John’s wort will be covered in the next column.

REFERENCES:

Natural Medicines Database accessed 3/5/2013

Scientific American Mind, volume 24, number 1, March/April 2013, pp 40-44.