Infant Skincare: Olive versus Mineral Oil - Reviewing the Evidence
Community Practitioner, Feb 2011
Pauline Carpenter & Karen
Richards
Abstract
In this paper, the Community
Practitioner Journal’s Education Supplement ‘Infant Skincare’, and the
associated research-based evidence that support the document are reviewed, in
order to establish whether olive oil should be considered detrimental to the
skin and that mineral oil should be deemed as the first choice for baby skin
care regimes. It was established that
the application of solutions of oleic acid was the main focus of the evidence
used to support the articles in the supplement and not olive oil, as is
implied. Also many of the statements
made about olive oil and mineral oil were unsubstantiated and further
investigation failed to support the claims asserted. This review includes information about the
chemical components of oils commonly utilised for massage and other skin care
regimes, in order to indicate that olive oil cannot be dismissed and that
mineral oil should still be used with caution until clear evidence-based
research has been found.
_________________________________________________________
The Educational Supplement
‘Infant Skincare’, which accompanied the October 2010 Community Practitioner
journal, prompted many parenting practitioners, who teach infant massage to
parents, to question both the arguments posed in the supplement and their
current practice vis-à-vis the supply of oils and the advice they give to
parents. The majority of infant massage
teacher training providers and subsequently infant massage teachers, throughout
the UK, encourage the use of vegetable oils for massage and suggest that
mineral oil should be avoided. The
Infant Skincare articles[1],
[2],
on the contrary, suggest the opposite!
As these are supported by, what appears to be, a good deal of
research-based evidence, confusion and uncertainty as to the advice to give
parents now exists.
Olive oil – revisiting the
evidence
Having reviewed the articles in
the supplement and, in particular, the research-based evidence associated with
the effect certain oils1 (mainly olive oil and mineral oil) have on
the skin, this review hopes to clarify the situation and alleviate any concerns
parenting practitioners may have. The
articles in question1, 2 are well referenced, but many statements
within them are not. For example, the assertion,
in the educational supplement that: ‘evidence
suggests that olive oil can be damaging to the skin barrier’ (page 511)
was not referenced. This review has
undertaken an extensive search for some form of evidence to support the
statement, rather than simply dismissing this claim.
The majority of research
referred to1 and used as supporting
evidence by the supplement, concerns the application of solutions of oleic
acid, which is argued to be a major constituent of olive oil. However, these studies[3],
[4], [5], [6]
do not give consideration to natural vegetable oils and are not concerned about
the on-going health or repair of the skin.
Instead they concentrate on substances that are actually efficient at
breaking down the skin barrier, in order to aid skin penetration to enhance
drug absorption.
To date, only one study[7]
has been found that compares the impact of topical oils on skin barrier
function. The study included olive oil
and its effect when applied to damaged skin; although this was not the main
focus of the enquiry. The study7 directly investigated the effect of
vegetable oils on the recovery of skin barrier function of mice after acute
barrier disruption by tape-stripping had been carried out. The results showed
that a single application of sunflower oil accelerates recovery of barrier
function, mustard oil has the most deleterious effects on barrier function and
olive oil delays the skin barrier recovery.
Therefore, suggesting that it is inadvisable to put olive oil on already
damaged skin; not that it can damage the skin barrier. It is necessary to point out that
compromised/damaged skin is a contraindication to massage, regardless of the
oil applied8.
It is indicated in the educational supplement that the percentage of
oleic acid content in olive oil is ‘55%
to 83%’ (page 51).
Drawing on the results of the above mentioned study7, the sunflower oil evaluated had 29.6% oleic
acid content, with 58.3% linoleic acid and an undetectable level of erucic
acid. (The usual range for a sunflower
oil is - Linoleic Acid 48% -74 %; Oleic Acid 14% – 40%)9. One
of the mustard oils tested7 was found to
have an undetectable level of oleic acid, with 34.1% of linoleic acid content
and 41.5% erucic acid. There was no
reference made regarding levels of linoleic acid or erucic acid, in the olive
oil used in the tests.
This begs the question, could
it be the erucic acid content found in the mustard oil that is the damaging
factor within the oil? Particularly as the level of oleic acid present in the
mustard oil was undetectable, yet the mustard oil still proved to be damaging
to the stratum corneum. Furthermore,
sunflower oil has the potential of having a comparatively high level of oleic
acid9, whilst containing potentially
high linoleic acid and low erucic acid7. Evidence of the usual levels of linoleic and
erucic acid within olive oil were not quoted in the supplement. However, during the search for relevant
information for this review, it was found that the usual percentage range of
linoleic acid in olive oil is 3.5% - 21%10;
but levels of erucic acid could not be established.
In direct contrast to the claim
in the Educational Supplement that olive oil has potential for harm, a study11 looking at the effects of daily treatment
with an olive oil/lanolin cream, applied to undamaged skin in preterm infants,
showed that treatment with this cream lowered the risk of dermatitis and was
superior to Bepanthen, a commonly used emollient.
Exploring the concept of fatty acids in vegetable oils
This information can be explored more deeply, by
giving much more consideration to the chemistry behind the above percentages
and what they mean in reality. Vegetable
oils contain free fatty acids, as well as triglycerols, which are fatty acids
bound to a glycerol molecule. The figure often quoted as fatty acids present in
any particular oil is the total percentage of triglycerols and free fatty
acids. (For example, the main constituents of olive oil and sunflower oil, as
quoted above, are the total levels of triglycerols and free fatty acids.) In a
given quantity of extra virgin olive oil, the free fatty acid present is
usually well under 0.8%10. The majority of fatty acids found in olive oil are
bound to glycerol making them chemically less active. Therefore, the measurement of total fatty
acid content is not a true measure of the reactivity of an oil. A more accurate
measure of an oil’s reactivity would be the amount of free fatty acid
present.
In the research papers reviewed,3,4,5,6 the substance used is not natural olive oil but a fabricated solution
of pure oleic acid (1% - 15%) dissolved in ethanol, propylene glycol or MYRITOL
318. The oleic acid solutions were applied to mouse, rat or human skin, which
was usually tape-stripped before testing commenced; a treatment that is known
to artificially compromise the epidermal barrier. The solutions used in the studies therefore
contained free fatty acid concentrations in excess of those found in natural
olive oil. It is difficult, therefore, to draw direct conclusions with regard
to natural olive oil from these studies.
Mineral oils
Regarding mineral oil and the
suggestion that it is a much safer oil to use for massage and skincare, the
articles1,2 in the supplement were interesting. These ‘facts’ were actually more difficult to
refute, as there seems to be extensive research that investigates unrefined or
partially refined mineral oil, but searching the internet for information on
refined (or ‘medicinal grade’1) mineral
oil proved to be fruitless. There is a
lot of confusion relating to the term ‘mineral oil’. Published articles relating to unrefined
mineral oil, indicate that it is carcinogenic.; but this has been taken to mean
that all mineral oils are carcinogenic without taking into account the refining
process. It is easy to tar all mineral
oil with the same brush, but that would openly invite criticism. The educational supplement1, has drawn conclusions from the research
about oleic acid, implicating olive oil as an ‘oil to avoid’ vis-à-vis infant
skincare. It is important not to have
the same knee-jerk reaction to the research relating to mineral oil, but
instead, assess the evidence supporting the arguments presented.
The supplement2 indicates that medicinal grade mineral oil
should be used for infant skincare and massage because it does not contain
oleic acid, is extremely inert and less likely to irritate the skin and,
contrary to popular belief, it is able to penetrate the skin as well as a
vegetable oil and therefore does not block the pores. These statements, like others in the articles
included in the supplement, are unreferenced.
There is no indication that there is any research to support these
claims in the supplement and research for this review also failed to find any
concrete evidence.
Furthermore, there is no
explanation of what ‘medicinal grade mineral oil’ is. If it is pure, unadulterated mineral oil,
then the problem arises that this is not readily available over the counter. It is actually quite difficult to obtain
(several unsuccessful attempts to do so were undertaken as part of the process
for this review) and it is generally only purchased in large quantities by
cosmetic companies. If ‘medicinal grade
mineral oil’ refers to the oil that is widely available commercially, then, as
it is mixed with at least a couple of additives, the question has to be, how
can this be beneficial for an infant’s skin?
Having investigated the
ingredients of three commercially available mineral oils, which are
specifically marketed for use with babies, the following chemicals were found:
Hexyl laurate, hydrogenated styrene and cyclopentasiloxane, which are all chemical
ingredients, commonly used by the cosmetic industry. One product sample included Prunus dulcis,
which is the Latin name for the almond tree.
Lavandula angustifolio, found in another, is the Latin name for
Lavender; and Bisabolol, found in one of the samples, is the main active
ingredient in Chamomile essential oil; and Chamomilla recutita, found in
another, is the Latin name for Chamomile. They also all contained ‘Parfum’,
which is perfume, but what perfume was used and what it contains was not
specified.
Firstly, the question, ‘Why put
unnecessary chemicals on a baby’s skin?’ has to be asked. Why let them potentially ingest, or absorb
ingredients that are of no benefit to them?
Furthermore, there is research12
to indicate that essential oils are potential endocrine disruptors and that
they should be avoided for prepubescent children. If a product is being applied regularly, over
a sustained period of time, there is a greater chance of an effect
occurring. Particularly in the case of
infant massage, parents are encouraged to massage as often as possible
(preferably every day), until their infant is at least crawling, but preferably
beyond8.
Having reviewed the Educational
Supplement, ‘Infant Skincare’, and the associated research papers, it is
difficult to draw a clear conclusion that olive oil per se is harmful to the
skin and that mineral oil is beneficial.
With specific reference to infant massage, sunflower, grapeseed and
fractionated coconut oils are considered the most suitable8, but olive oil is recognised as a safe
alternative, particularly when mixed with a lighter oil, such as sunflower8. This would have the further effect of
reducing the already low levels of free fatty acids present in olive oil. In addition, as the contraindications to
massage include infectious skin conditions, open, weeping wounds and rashes
(i.e. if the skin is damaged in any way), such application should not occur and
the safeguarding of the infants’ (skin) health would be assured.
[1]
Introduction by Fergie, G. (2010) Infant
Skincare: Common Myths about Baby Skincare. Community Practitioner - Educational
Supplement. 2: 4-5
[2]
Introduction by Fergie, G. (2010) Infant
Skincare: Implications for Practice. Community Practitioner - Educational
Supplement. 2: 10
[3]
Mélot, M., Pudney, P.D.A., Williamson, AM. &
Caspers, P.J. (2009) Studying the
effectiveness of penetration enhancers to deliver retinol through the stratum
corneum by in vivo confocal Raman spectroscopy. Journal of Controlled Release. 138: 32-39
[4]
Naik, A., Pechtold, L., Potts, R.O. & Guy, R.H.
(1995) Mechanism of oleic acid-induced
skin penetration enhancement in vivo in humans. Journal of Controlled Release. 37: 299-306
[5]
Jiang, S.J. & Zhou, X.J. (2003) Examination of the Mechanism of Oleic
Acid-Induced Percutaneous Penetration Enhancement: an Ultrastructural Study.
Biol. Pharm. Bull. 26(1): 66-68
[6]
Larrucea, E., Arellano, A., Santoyo, S. & Ygartua,
P. (2001) Combined effect of oleic acid
and propylene glycol on the percutaneous penetration of tenoxicam and its
retention in the skin. European Journal of Pharmaceutics and Biopharmaceutics.
52: 113-119
[7]
Darmstadt, G.L., Mao-Qiang, M., Chi, E., Saha, S.K., Ziboh, V.A., Black, R.E.,
Santosham, M. & Elias, P.M. (2002) Impact
of topical Oils on the Skin Barrier: Possible Implications for Neonatal Health
in Developing Countries. Acta
Paediatr. 91: 546-554
8 Carpenter, P. & Epple, A. (2009) Infant
Massage: The Definitive Guide to Teaching Parents. Ditto International Ltd.
11
Kiechl-Kohlendorfer
et al. (2008) The effect of daily treatment with an olive
oil/lanolin emollient on skin integrity in preterm infants: a randomized
controlled trial. Pediatr Dermatol. 25(2): 174-8
12 Henley, D.V. & Karach (2007) Prepubertal
Gynecomastia Linked to Lavender and Tea Tree Oils. The New England Journal
of Medicine. 356: 479-485
Chemical structures:
For clear information about the chemical structures of
oleic acid see:
posted by Pauline Carpenter @ 08:24
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