Diet, vitamins and skin care

Week by week, magazine articles carry dozens of suggestions as to how we could make our skin healthier. As we have seen, healthy skin is the consequence of a well-hydrated and intact epidermis, together with avoidance of sun damage and a balanced diet. When we are fatigued, poorly nourished or stressed, our skin shows it

While the use of daily vitamins has for years been recognized as an important part of maintaining health, only recently have researches started paying attention to the relationship between nutritional intake and skin health. Vitamins have long been used in topical skin treatment for their beneficial effects on their skin's surface and for their antioxidant properties, but obtaining skin benefits via ingested vitamins had not received much attention. Today, a number of studies reveal that certain vitamins and minerals, when taken internally, can positively influence skin appearance, beauty, and a woman's overall health.

As we have seen, healthy skin is the consequence of a well-hydrated and intact epidermis, together with avoidance of sun damage.

General guidelines for skin care

Whatever our nationality or race, our skin care habits have some similarities of objective, even if the degrees of sophistication of the products we use are very different.
    In theory 'normal' skin does not need any modification, since it is already well balanced with respect to its physiological and mechanical integrity. Nevertheless, this balance can be unstable to some extent, and therefore two essential approaches to the care of normal skin must be considered:

• maintenance of this balance, and
• protection from external injury.

The first aim is a passive one: it is more particularly concerned with avoiding products that are not active treatments as such, but may be harmful to the skin - harsh soaps, for example. The second plays a more active role, involving the use of photoprotective products and hydrating agents.
    Skin care, from the skin scientist's standpoint, means preserving the integrity of the stratum corneum while removing sebum and soiling and maintaining adequate moisturisation.
    For most women throughout many centuries, this was achieved by very harsh and primitive means. Even until relatively recently, the only skin and hair care product used by most people was a bar of harsh soap.
    Fortunately today's cosmetic industry is providing increasingly mild and sophisticated products at affordable prices which not only scientifically care for the skin, but also help to reduce the visible effects of aging.
    For most of us, skin care focuses on hands and face. Increasingly, however, industry is looking at the care of the body both in general and in specific areas, such as the delicate skin around the eyes, and good-quality products for these are now on the market.

  In the rest of this chapter, we look at particular types of skin care and the products that are required for them.

Facial care

In this section we outline some suggestions for facial care regimens for skin of different ages.

Young (teenage) skin

Typical skin type - oily /combination:

• remove make-up
• cleanse, using mild or light cleanser
• tone
• moisturize (using a light product, because of the presence of sebum) containing sunscreen ingredients that will block UVA/UVB.

Adult skin

Example skin type - normal to dry:

• remove make-up
• cleanse twice daily with a mild cleanser
• tone
• by day, use a medium moisturizer, with sunscreen ingredients (UVA/UVB)
• by night, use a heavier night cream without sunscreens
• moisturise hands regularly.

Elderly skin

Usual skin type - dry:

• cleanse with cream cleanser
• use heavy-duty moisturizer daily with sunscreen
• always use a night cream.

Skin cleansing

The aim of cleansing is to remove:

• surface dirt
• all make-up
• the top layer of dead skin cells
• potentially harmful micro-organisms (bacteria).

The way in which any individual chooses to carry out this process is determined by habit, skin feel requirements and activity.

What goes to make a cleansing product?

For many generations soaps have been made by the extraction of oils and tallows from plants and animals and then treating these with alkalis to neutralise the fatty acids they contain. Soaps are good emulsifiers (that is, they hold solids and oils in liquids in emulsion form so that they can be rinsed away), they have reasonable lathering power and an emollient action. Unfortunately, two problems are associated with soaps.

Firstly, because of their powerful cleansing action, overuse may completely eliminate the protective lipid film on the skin surface, which helps maintain the skin's physiological balance. As a result they may give rise to irritation.

Secondly, some soaps are alkaline (they have a high pH, around 9). Since skin pH is about 5, washing with soap leads to pH increases on the skin that can last for up to two hours.

'Oily' soaps are enriched with emollients such as glycerol, fatty acids or oils, which have a softening and smoothing action. They can leave the skin softer than ordinary soap does by avoiding excessive removal of lipids from the skin surface, but they suffer from the same pH problem.

Most hygiene products contain ingredients called surfactants (or sometimes detergents). The terms include a wide range of substances, all of which are effective to a greater or lesser degree in dispersing greasy materials in water. Scientists call these greasy materials hydrophobic, from the Greek words meaning 'water-hating' because oils will not mix with water unless 'helped' by a surfactant. Soaps are surfactants, strictly speaking, but the term is usually kept specifically for man-made (synthetic) surfactants.

Surfactants are found in laundry detergents, liquid cleansers, shampoos and shower products. Their chemistry makes it possible for them to remove soiling from many different materials, including skin and hair, so that oil and grime can be rinsed away. Some surfactants are harsh to the skin while others are very mild, depending on their type. Based on this wide variety of available surfactants, not all cleansers ar the same. It is important to use products that best fit your skin type.
    Surfactants are classified according to their structure:

• cationic surfactants (ammonium compounds): these are poorly tolerated by most people's skins, and are now hardly used at all in skin care products
• anionic surfactants such as sodium lauryl sulphate - their molecules have a negatively charged 'head' and a long hydrophobic 'tail'; these are widely used because of their good lathering and detergent properties
• amphoteric surfactants such as the betaines, and alkylamino acids - these are well tolerated and lather well, and are used in shampoos
• non-ionic surfactants such as sucrose esters - overall these molecules are uncharged; these are tolerated better than other types, but do not lather particularly well.

Syndets (short for 'synthetic detergents') are mixtures of synthetic surfactants, mainly anionic surfactants with some added amphoteric surfactants to improve their tolerability. Their potential lies in the fact that their pH may be adjusted to that of skin, and they can be enriched with oily compounds.

To best maintain the skin surface's physiological balance, it may be better to use syndets rather than soaps for all personal cleansing. This is especially true for young children, whose skin is more delicate than adult skin. It is also true for the sensitive skin of the scalp, for which the best care centres on the use of a mild shampoo formulated for frequent use.