Free radical damage is one of the principal mechanisms of aging. Free
radicals are highly and indiscriminately reactive chemicals that can damage any
structure in living cells. The most common source of free radicals is normal
burning of fuel that occurs in every cell every minute of every day. (Generally,
the more free radicals a species produces, the shorter its life span.) Skin
suffers additional free radical damage from sunlight and pollutants.
Topical antioxidants provide some protection against environmental damage to
the skin and may be somewhat effective in slowing down the skin aging. However,
topical antioxidants are relatively unreliable. Their effect depends on skin
permeability, other ingredients in the cream and many other factors. It appears
that increasing oral intake of some antioxidants may additionally protect skin
from free radicals. Keep in mind, however, that relatively little solid research
has been done specifically on skin benefits of oral or topical antioxidants and
much of the supporting evidence is indirect.
A very important chemical property for an oxidant is its solubility in water
and fat (or oil). Basically, living organisms have two types of internal media,
watery extra- and intracellular space and oily membranes that serve as
partitions enclosing individual cells and various intracellular compartments.
Water-soluble antioxidants are effective mainly in extra- and intracellular
fluid, whereas fat-soluble antioxidants protect biological membranes. Both types
of antioxidants are needed to create an effective shield against free radicals
for the entire body, and skin in particular.
Solubility of antioxidants
Below we review some of the antioxidant nutrients and supplements which
appear the most likely to produce skin benefits.
Vitamin E
Vitamin E is a principal fat soluble antioxidant vitamin in the body. It
protects cellular membranes, lipoproteins and other "oily" structures. Skin is
high in unsaturated fatty acids ("oily" molecules especially susceptible to free
radical damage), and can benefit from vitamin E protection (both oral and
topical).
Flavonoids
Flavonoids are a diverse group of plant pigments with antioxidant properties.
These substances are responsible for color in many fruits, vegetables and
flowers. In addition to providing color that attracts insects or animals, these
pigments protect plants from environmental stress. In addition to being potent
antioxidants, some flavonoids have antiallergic, anti-carcinogenic, anti-viral
and anti-inflammatory activity. Over 4,000 flavonoids have been characterized
and classified, but only a few have been researched. As far as skin benefits are
concerned, two classes of flavonoids appear to be especially beneficial:
proanthocyanins (found in grapes and pine bark) and polyphenols (found in green
tea).
Coenzyme Q10, Lipoic acid, Cysteine, Methionine
Coenzyme Q10, lipoic acid, cysteine and methionine are potent antioxidants.
But they also play other roles that are at least as important as their
antioxidant activity. See also the article about conditionally essential
nutrients in this section.
