Photograph © Colin Dunn |
Understanding How They Help (and When They Might Harm)
___________________________________________________________________________________
Proper nutrition is as important to
the long-term health and well-being of a person living with HIV as it is to anyone else. But oftentimes,
dietary needs require adjustments as the body responds to different medications
or the disease itself.
Vitamins and minerals can often be
depleted during severe or prolonged bouts of diarrhea, the condition of
which can induced by certain infections or medications.
Changes in body fats, also
associated with treatment or HIV infection,
can demand marked changes to one’s diet.
Far more concerning, however, is the
impact on malnutrition on people with HIV. Vitamin A and B-12 deficiency, for
example, has been associated with faster disease progression in both
resource-rich and resource-poor settings. Low serum levels of micronutrients,
commonly seen in malnourished individuals, demand greater vitamin intake—often
in the way of nutritional supplements.
Without question, nutritional
supplements have their place in the treatment of malnutrition or a diagnosed
deficiency, whether it be caused by an HIV-related condition or poor nutrition
itself. This is particularly true in late-stage disease when weight loss and HIV wasting are frequently
seen.
But what about everyone else? Do
people with HIV inherently need nutritional supplements? Do these products
complement therapy in a way that either reduces the incidence of infection,
delays disease progression, or reconstitutes a person’s key immune functions?
Or are we just hoping they will?
Putting
the Supplements Industry into Context
According to the U.S. Centers for
Disease Control and Prevention (CDC), nearly half of all Americans consume dietary supplements,
including vitamins, minerals and herbals. This expansive range of products is
regulated by the U.S.
Food and Drug Administration (FDA),
which defines dietary supplements simply as products “intended to add further
nutritional value to (supplement) the diet.”
In accordance with this definition,
multivitamins and other nutritional supplements are regulated as a category of
food, rather than as a pharmaceutical product. They neither have to go through
stringent, pre-market safety and effectiveness testing, nor does the FDA have
the authority to require such testing.
Instead, the FDA relies primarily on
post-market surveillance—monitoring consumer complaints and requiring
manufacturers to maintain of a roster of adverse events. However, these adverse event reports (AERs)
are only sent in instances of serious to life
threatening side effects. Mild to
moderate events, such as headache or gastrointestinal distress, are not
reported unless the manufacturer voluntarily chooses to do so.
This is in stark contrast to the
pharmaceutical industry, which spends an average of $1.3 billion dollar per
drug in research & development costs in order to obtain FDA approval.
In 2011, sales of dietary
supplements hit $30 billion in the U.S., more than twice the size of the global HIV drugs market.
Can
Supplements "Boost" Immunity?
Good nutrition by means of a
balanced diet can help ensure proper immune function in conjunction with
the timely and informed use of antiretroviral medications.
The role of vitamins and other nutritional supplements, by contrast, remains
debatable.
Confusion is rife in the consumer
marketplace, often fueled by manufacturer claims about products which are
thinly supported by research. And while the FDA tries to regulate these claims,
a 2012 assessment by the Department of Health and Human Services reported that
as much as 20% of the supplements reviewed made wholly prohibited claims,
oftentimes around the issue of “immune support.”
It’s not so much that these claims
are patently false. It simply that the evidence referred to is generally
inconclusive or anecdotal at best.
A number of manufacturers, for
instance, regularly point to a 2004 study by the Harvard School of Public
Health, which looked at the effect of multivitamins on disease progression in
1,097 HIV-positive, pregnant women in Tanzania. At the end of the trial, 31%
who had taken the supplements had either died or acquired an AID-defining illness versus
25% in placebo group.
Based on this evidence, the
researchers concluded that the daily use of a multivitamins (specifically B, C
and E) not only delayed HIV progression, but provided “an effective, low-cost
means of delaying the initiation of antiretroviral therapy in HIV-infected
women.”
Upon publication of the research, a
number of manufacturers pointed to the study as “scientific proof” of their
product’s immune-boosting properties. What most failed to do, however, is
contextualize the study, ignoring the numerous co-factors that contributed to
the results—not least of which are the high levels of poverty, hunger and
malnutrition that exist within an indigent African population.
Ultimately, nothing in the study
suggested that multivitamins, in and of themselves, would demonstrate the same
benefits—or afford the same conclusions—in the resource-rich settings like the
U.S. or Europe.
Results from follow-up studies have
been largely inconsistent, including a 2012 study which showed that high-dose
multivitamins might actually increase the risk of death in severely
malnourished individuals. Others clinical studies have shown benefits only in
those with advanced disease (CD4 counts under 200
cell/mL), while others still have shown no benefit at all.
What most studies have supported is
the safety of multivitamins in recommended daily doses, particularly for
people with HIV who are either undernourished or in advanced stages of disease.
When
Supplements Do More Harm Than Good
Far less is known about the benefits
of individual vitamins, minerals, and other trace elements. A number of studies
in recent years have focused on the role of selenium, a non-metal
mineral with known antioxidant properties. Research seems to suggest that the
loss of selenium in early HIV infection parallel the loss of CD4 cells at a
time when malabsorption and malnutrition are generally not seen to be factors.
As compelling as this relationship
might seem, research has not yet been able to support any true benefit of
selenium supplementation, either in the avoidance of HIV-related illness or the
reconstitution of CD4. Similar results have been seen with magnesium and
zinc supplements, whereby increases in plasma levels have had no correlative
association to either disease progression or outcome.
The prolific use of supplements by
some HIV-positive people is underpinned by the belief that “natural” products
provide natural immune support that can readily complement HIV therapy.
This is often not the case. In fact,
a number of supplements can have a profoundly negative impact on people
with HIV, either by interfering with the metabolism of their drugs or by
causing toxicities that mitigate any possible benefit of supplementation.
Among the potential concerns:
- Megadose Vitamin A – High doses of vitamin A (above
25,000 IUs daily) can increase the risk of liver toxicities, internal
bleeding, spontaneous fractures, and weight loss. The World Health Organization (WHO) does not recommend the use of vitamin A supplements in
pregnant, HIV-positive women, with research showing that a daily 5,000 IU
dose might actually increased the risk of mother-to-child transmission.
- Megadose Vitamin C – While some research has suggested
that high doses of vitamin C may play a significant role in cellular
immunity, evidence is highly contradictory. What we do know is that
high doses of vitamin C can cause gastrointestinal distress and diarrhea
(the latter of which can impact absorption of certain HIV medications).
Vitamin C doses above 1000 mg per day are also known to reduce Crixivan (indinavir)
levels in some.
- Vitamin B6 (pyridoxine) – Excessive intake of vitamin
B-6 (above 2,000 mg per day) can cause reversible nerve damage,
exacerbating peripheral neuropathy
in HIV-positive patients already affected by the condition.
- Vitamin E – High doses of vitamin E (above 1,500 IUs)
can interfere with blood clotting, while prolonged, excessive use can
result in diarrhea, muscular weakness, and nausea.
- St. John’s Wort (hypericin) – An herbal
preparation popularly used to treat mild depression, St. John’s Wort is
known to reduce the levels of all protease inhibitor (PI) and
non-nucleoside reverse transcriptase inhibitor (NNRTI)-class drugs,
putting the patient at risk of drug resistance and treatment failure.
- Garlic – Garlic pills and supplements have been shown
to reduce serum levels of certain HIV drugs, particularly Invirase (saquinavir)
which can be reduced by half when taken concurrently with garlic
supplements. By contrast, fresh or cooked garlic are not seen to affect
serum drug levels.
- Grapefruit Juice – An 8 oz. glass of fresh grapefruit juice taken with Crixivan can reduce serum drug levels by 26%, while a similar size glass can increase Invirase levels by up to 100% (increasing potential side effects). While grapefruit juice should not necessarily be omitted from one’s diet, it should not be taken either two hours before or two hours after a drug dose.
Take
Home Messages
The importance of proper nutrition
and healthy, balanced diet cannot be overstressed. Nutritional counseling may
help those with HIV better understand their dietary needs in order to better:
- Achieve and maintain a healthy body weight.
- Maintain healthy lipids levels, including cholesterols and triglycerides.
- Foresee dietary complications that may result from some antiretroviral medications.
- Address dietary complications that may arise from HIV-related symptoms.
- Implement food measures to avoid possible food-borne opportunistic infections.
The role of exercise cannot be
ignored, with benefits to both physical and mental health (including a reduction
in the risk in HIV-associated neurocognitive
impairment).
In terms of supplementation, a daily
multivitamin can help ensure that micronutrient needs are met, particularly in
those unable to achieve nutritional goals.
However, taking vitamins in excess
of their recommended daily allowance is not advised. There is also no data to
support the use of herbal supplements in either treating HIV infection or
increasing the efficacy of antiretroviral drugs by reducing the HIV viral load.
Please advise your doctor of any
supplements you may be taking when discussing the management and treatment of
your HIV.
Sources:
U.S. Centers for Disease Control and
Prevention (CDC). “Dietary Supplement Use Among U.S.
Adults Has Increased Since NHANES III (1999-1994).” NCHC Data
Brief. National Center for Health Statistics; Hyattsville, Maryland; April
2011; Number 1.
Fawzi, W.; Msamanga, G.;
Spiegelman, D.; et al. “A randomized trial of multivitamin
supplements and HIV disease progression and mortality.” New
England Journal of Medicine. July 2004; 351(1):23-32.
Isanaka, S.; Mugusi, F.; Hawkins, C;
et al. “Effect of high-dose vs standard-dose multivitamin
supplementation at the initiation of HAART on HIV disease progression and
mortality in Tanzania: a randomized controlled trial.” Journal of
the American Medical Association. October 17, 2012; 308(15):1535-1544.
Constans, J.;
Delmas-Beauvieux, M.; Sergeant, C.; et al. “One-year antioxidant supplementation with beta-carotene or
selenium for patients infected with human immunodeficiency virus: a pilot
study.” Clinical Infectious Diseases. September 1996;
23(3):654-656.
Villamor E.; Msamanga, G.;
Spiegelman, D.; et al. “Effect of multivitamin and vitamin A supplements on weightgain during pregnancy in HIV-1-infected women.” American Journal
of Clinical Nutrition. December 7, 2001; 76(5):1082-1090.
_______________________________________
Read more articles from Very Well, here.
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.