[pronut-hiv] Enveloped viruses and lipids

[Pamela Morrison <pamela@ecoweb.co.zw>]

The antiviral effect of lipids in human 
milk.
Pamela Morrison
--------------------
Judy

Thank you for bringing up such an interesting topic as the effect of lipids 
on enveloped viruses - particularly the antiviral effect of lipids in human 
milk.  A considerable amount of research has in fact been done on this, but the interesting thing is that what should logically be a promising area for further study suddenly peters out. One of the reasons could be that the human milk fat globule appears to have attracted a certain amount of 
commercial interest.  If anyone belongs to Lactnet, a search of the 
archives would probably reveal some interesting postings on this.

I'm quoting a couple of excerpts below from an article I wrote which was 
published in Breastfeeding Review in 1999, and a section of it explores the role of lipids in human milk, with special reference to HIV.   You'll see I 
cite similar research to that mentioned in the coconut milk website.

Pamela Morrison
International Board Certified Lactation Consultant
Harare, Zimbabwe
------------
ANTIVIRAL PROPERTIES OF HUMAN MILK
.
In the 1960s and1970s a number of researchers looked at the antiviral 
properties of breastmilk, which showed the dual nutritional and antiviral 
role of lipids (Arnold 1993, Kabara 1980).   Lipid components that 
inactivate enveloped viruses were described.  (Sarkar et al 1973, Welsh et al 1979). In the late 80s and early 90s other researchers continued these investigations. They looked at the inactivation of enveloped viruses by different classes of free fatty acids in milk.   The most active free fatty 
acids were the polyunsaturated long-chain fatty acids (C16-C22) and the 
medium-chain saturated fatty acids (C10 - C14),  monoglycerides of  these fatty acids being the most active, sometimes at concentrations much less than the corresponding free fatty acids (Isaacs et al 1986, Thormar et al 1987, Orloff  et al 1993).

The fatty acids were found to affect the viral envelope, causing leakage 
and, at higher concentrations, a complete disintegration of the envelope 
and the viral particles.  They also caused disintegration of the plasma 
membranes of tissue culture cells resulting in cell lysis and death.   All 
enveloped viruses exposed to antiviral milk lipids or milk stomach contents 
were inactivated, including vesicular stomatitis virus (VSV), herpes 
simplex virus type 1 (HSV-1),  visna virus and HIV-1.  The antiviral 
activity, which reduced titers of virus by as much as 10 000-fold only 
affected enveloped viruses and was localized in the milk lipid 
fraction.  Its appearance in stored milk was apparently due to fatty acids 
released by the activity of milk lipases, particularly lipoprotein 
lipase.  Antiviral activity in the infants' stomach most likely resulted 
from the activity of gastric and lingual lipses on milk triglycerides and 
caused the release of antiviral fatty acids.    Milk and stomach contents 
that were antiviral also lysed cultured cells by disruption of their plasma 
membrane.  Cell lysis was also caused by purified linoleic acid, which is a 
normal constituent of human milk triglycerides.  (Isaacs 1986).  The HIV-1 inactivating property is heat stable and remains after heating at temperatures consistently used by milk banks (Orloff, 1993). Nduati et al (1995) note that culture detection of replicating HIV-1 virus in breastmilk remains a challenge because of inhibitory factors in human milk.

EXPRESSED HUMAN MILK WHICH IS ALLOWED TO STAND

The antiviral activity described above appeared after human milk had been stored at various temperatures for various lengths of time.   It is 
possible therefore that a virus may infect the infant before the milk 
becomes antiviral, whereas expressed human milk which has undergone storage with its accompanying lipolysis may have an antiviral advantage.

McDougal (1990) noted the antiviral activity of  milk lipids against HIV in 
spiked milk samples that sat on the counter as controls while other samples were being heat-treated.   Orloff (1993) noted that input HIV-1 
titer  could not be recovered from control human milk preparations that 
were innoculated with HIV, but not heated.  She states that this was due to inactivation of HIV-1 infectivity by the human milk, rather than to 
cellular toxicity or interference with detection of viral 
replication.  Isaacs and Thormar (1990) state that the appearance of this 
antiviral activity is lipoprotein-lipase dependent and occurs only in 
stored milk in which the lipase has had a chance to break lipids down into 
free fatty acids.  The activity of the free fatty acids is cumulative (the 
more that are present, the more effective the antiviral activity) and viral 
killing is rapid when the free fatty acids come into contact with the 
envelope of the virus.  In cases such as HIV infection, in which the virus 
may be found in the acellular fraction of the milk as well as the cellular 
fraction, these antiviral lipids may reduce the risk of viral transmission 
by destroying the free virus.  Milk concentrations as low as 10% had some 
anti-viral activity. Titer reduction occurred rapidly, within 5 - 10 
minutes and was more efficient at 37 degrees C and 22 degrees C than when HIV-1 was mixed with milk at O degrees C (Orloff , Wallingford & McDouga 1993).   Although the study was done to assess the effectiveness of  Holderpasteurization in destroying the HIV virus in  human milk, the researchers stated that the magninitude of inactivation cannot be attributable to heat alone although required concentration for maximum viral inactivation varies.

Later studies (Nduati et al 1995, Lewis et al 1998) conducted to determine 
the number of HIV-1 infected cells in breastmilk, and the quantity of HIV-1 
in cell-free breastmilk,  in order to determine the quantity of virus that 
may be consumed by the breastfed infant, contributing to vertical 
transmission of HIV-1, appear to have been done on breastmilk samples that have had the lipid layer removed and discarded.

More research is needed on the possibility of using breastmilk which has 
been allowed to stand for various lengths of time as a replacement feed for infants of HIV-infected mothers who have been advised not to breastfeed. We need to know the length of time that breastmilk would need to be stored at various  temperatures and under different conditions, that would be likely to maximize the anti-viral action while minimizing bacterial contamination.




-------------------------------------------------------------------------------------
>Judy Canahuati wrote:

>Dear all,
>
>While looking at this website for information related to virgin coconut oil
>and hypothyroidism
>http://www.coconut-info.com/links.htm , I came across the lauric.org's
>website. They have a human milk project that is attempting to do some 
>research on the possibility that
>increasing  lauric and capric acid levels in human milk, may protect 
>infants from MTCT. Lauric acid is a medium chain fatty acid that is rich 
>in coconut oil.
>http://www.lauric.org/milkproject.html 
>http://www.lauric.org/protocol_a-0118_1.jpeg 
>
>There is also a book on nutrients and HIV that I looked at. There is an 
>excerpt from one of the chapters.
>
>Also, browsing further I found the following:
>
>Why a Human Milk Project? Human milk fat has a unique fatty acid
>composition. It is approximately 45 to 50 percent saturated, about 35
>percent monounsaturated and 15 to 20 percent polyunsaturated. Of the
>saturated fatty acids made in the mammary gland, up to 18 percent can be
>the antimicrobial fatty acids lauric acid and capric acid. These
>antimicrobial fatty acids give the infant protection against viruses such
>as HIV (when you click on this it goes to this page, which has information
>on what lipid coated viruses are inactivated by lauric acid)
>http://www.lauric.org/lcv.html and herpes, bacteria such as chlamydia and
>heliocobater, and protozoa such a giardia lamblia.
>The levels of these antimicrobial fatty acids can be as low as 3 to 4
>percent, but as noted below, when lactating mothers are fed coconut fat,
>which is readily available food products that contain desiccated coconut,
>coconut milk, etc., the levels of lauric acid and capric acid increase
>significantly in the milk (see below for quote from study published in 1998
>in the American Journal of Clinical Nutrition). This gives an important
>added benefit; the milk supply has increased amounts of the protective
>antimicrobials lauric acid and capric acid, which will give even greater
>protection to the infant.
>
>
>Probable Levels of Lauric Acid Required For Antimicrobial Effect Based on 
>the amount of lauric acid found in human milk, which is known to be 
>effective in its role as an antimicrobial component for the infant, the
>percent of calories that would be appropriate can be determined. For 
>example, human milk provides at least 3.5% of calories as lauric acid for 
>the human infant. Mature human milk has been noted to have up to 12% of the
>total fat as lauric acid (approximately 6.6% of calories. The upper end of 
>this range represents approximately twice the amount of calories as lauric 
>acid (i.e., 7% of calories) as does the minimum. When developing 
>lauric-rich diets for adults, one can use this range as the starting point 
>for calculating the amount of lauric fat to be consumed.
>Based on the upper end of the range, we see that this would entail 
>providing an adult consuming 3000 kilocalories a day with 52 grams of 
>coconut oil (approximately 24 grams of lauric acid). This could be 
>accomplished by use, for example, of two 250 ml cans of a calorically 
>dense enteral formula (e.g., Carnation Nutren 2.0) if that product was 
>made with full coconut oil. As it is, that product is made with MCT oil 
>and corn oil and provides no lauric acid.
>
>Lauric acid-rich diets can be developed readily for infants and children.
>For infants, a formula made with coconut oil that supplies at least 7% of
>the calories as lauric acid would be needed. When infants progress to solid
>food, these foods can be enriched with added coconut oil. Cereals and
>strained baby foods make ideal bases for 2-5 gram additions coconut oil
>(0.5-1.0 teaspoons). This would add approximately 1-2 grams of lauric acid.
>Children can utilize the same protocol as outlined for adults with
>alterations in the portions of food depending on the caloric needs of the 
>child
>
>
>Does anyone know anything about this?
>
>Judy
--
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