Slide 2
The following topics will be discussed in this tutorial:
- What is the effect of HIV and AIDS on nutrition?
- What is the impact of nutrition intervention on HIV disease
progression and mortality?
- What are the nutritional considerations with respect to the
transmission of HIV from mothers to infants?
Additional recommendations for nutrition care and support are addressed
in the Nutrition Care and Support tutorial.
Slide 3
Let’s begin with a discussion of the forms of malnutrition that are
common in resource-poor settings.
Malnutrition takes many forms. These include protein-energy
malnutrition (PEM) and micronutrient malnutrition.
Protein Energy Malnutrition is usually measured in terms of body size,
such as weight, height, body fat and muscle mass.
Micronutrient malnutrition is more difficult to measure. It is often
called ‘hidden hunger’ because it is difficult to recognize until it
becomes severe. Iron, vitamin A and iodine are the most commonly reported
micronutrient deficiencies in children and adults.
Deficiencies of other micronutrients that are vital for the body’s
normal functions, including the work of the immune system, also frequently
affect women living in resource-poor settings, particularly if they suffer
from infectious diseases and food insecurity.
Slide 4
When women are malnourished, the entire family is affected.
Micronutrient deficiencies increase the risk of maternal morbidity and
mortality.
- Zinc and vitamin A deficiencies weaken the mucosal barrier and
increase the risk of sexually transmitted infections.
- Low calcium intake increases risks of pre-eclampsia, high blood
pressure and hypertension during pregnancy.
- Iron deficiency reduces resistance to disease, causes fatigue and
reduces women’s productivity.
- Anemia, primarily due to iron deficiency and made worse by malaria,
hookworm, HIV, and other infections, increases the risk of maternal
death due to hemorrhage and other causes. Anemic women are also more
likely to have prolonged labor which increases the risks of sepsis,
HIV transmission and death.
Maternal nutrition before and during pregnancy also affects infant
birth outcome and health. Maternal malnutrition increases the risk of
intrauterine growth retardation (IUGR) and low birth weight (LBW), and it
reduces stores of some nutrients that infants need for growth and
development. Intrauterine growth retardation and low birth weight increase
the risks of growth faltering, and of neonatal and infant mortality. For
all of these reasons, nutrition assessment and care are important elements
of clinical care for women living in resource-poor settings.
Slide 5
Malnutrition and HIV affect the body in similar ways.
In individuals, both conditions affect the capacity of the immune
system to fight infection and keep the body healthy.
As shown in this slide, changes in the immune function due to
malnutrition are very similar to those caused by HIV and AIDS.
For many years, before the AIDS epidemic, the impairment to immune
function caused by malnutrition was called the "Nutritionally
Acquired Immune Deficiency Syndrome" or NAIDS.
So, in resource-poor settings, HIV infection on top of pre-existing
malnutrition creates a tremendous burden on people’s ability to remain
healthy and economically productive.
Slide 6
HIV affects nutrition in three, sometimes overlapping, ways:
It has symptoms that cause a reduction in the amount of food consumed;
It interferes with the digestion and absorption of nutrients consumed; and
It changes the metabolism, or the way the body transports, uses, stores
and excretes many nutrients
Slide 7
Decreased food consumption may be due to causes such as:
- painful sores in the mouth and throat or from
- fatigue, depression and changes in mental state
Decreased food consumption may also result from side effects of
medications -- such as nausea, vomiting, metallic taste in the mouth,
diarrhea, abdominal cramps and loss of appetite.
Finally, economic factors, such as inability to work or reductions in
income because of HIV-related illnesses, can affect household food
security and the nutritional quality of the diet.
Slide 8
HIV-infection also interferes with the body’s ability to absorb
nutrients, an effect that occurs with many infections.
Studies suggest that poor absorption of fats and carbohydrates occurs
at all stages of HIV infection in both adults and children and results in
excess nutrient loss.
Poor absorption is caused by:
- HIV-infection of the intestinal cells which may damage the gut, even
among people who have no other symptoms of infection, and by diarrhea,
which is a common cause of weight loss in people living with HIV.
- Poor absorption of fat, specifically, reduces the absorption and use
of fat-soluble vitamins (such as vitamins A and E). This can further
compromise nutrition and immune status.
Slide 9
Changes in metabolism also occur as a result of the immune system’s
response to HIV infection. When the body mounts its acute phase response
to infection, it releases pro-oxidant cytokines and other oxygen reactive
species. These cytokines produce several results. One is anorexia (causing
lower intake), and another is fever (increasing energy requirements). If
the infection is prolonged, muscle wasting occurs because muscle tissue is
broken down to provide the amino acids that immune proteins and enzymes
need. These processes increase energy requirements by at least 10-15% and
protein requirements by 50% or more. The body responds to this release of
pro-oxidant cytokines also by increasing the demand for antioxidant
vitamins and minerals, such as vitamins E and C, beta-carotene, zinc and
selenium. These vitamins and minerals are used to form antioxidant
enzymes. Oxidative stress occurs when there is an imbalance between the
pro-oxidants and antioxidants -- in other words, when there are not enough
antioxidants to meet the demands of the pro-oxidant cytokines. This stress
is believed to increase HIV replication and transcription, leading to
higher viral loads and disease progression. For this reason, many studies
have examined the impact of antioxidant vitamin supplementation on HIV
transmission and disease progression.
Slide 10
As seen in this slide, malnutrition and HIV form a vicious cycle where
each condition worsens the other.
This cycle results in:
- Weight loss
- Loss of muscle tissue and body fat
- Vitamin and mineral deficiencies
- Reduced immune function and competence
- Increased susceptibility to secondary infections
- More rapid HIV disease progression
Slide 11
Now we will address the question, "Can improved nutrition slow HIV
disease progression?"
Slide 12
Early studies, which observed associations over time without providing
any specific nutrition interventions, showed that nutritional status and
HIV were inter-related. These studies reported that weight loss in
individuals was associated with HIV infection, disease progression and
shorter survival time.
Studies also found that low blood levels of several nutrients,
including vitamins A, B12, E, and selenium, iron and zinc, were associated
with faster HIV disease progression and reduced survival, after taking
into account the patient’s use of antiretroviral drugs, their immune
status and their diet.
But these observations alone do not let us know whether the nutritional
deficiencies caused or resulted from HIV progression.
Controlled clinical trials are required to learn whether improving
nutrition can impact HIV progression and prolong patient survival.
Slide 13
Since the 1980’s there have been a number of controlled clinical
trials studying the effects of nutrition on HIV. Many were on patients
with AIDS, but some were also done on patients at early stages of HIV
infection. From these studies, we observe that nutrition supplementation
and counseling interventions may reduce HIV patients’ vulnerability to
weight loss and muscle wasting. This effect is confirmed particularly when
nutrition supplements are given in the early stages, at a time when low
dietary intake and poor nutrient absorption are the primary causes of
weight loss. Later in the course of infection, when metabolic changes
begin to play a leading role in the wasting process, other types of
intervention are required. In one study, HIV-positive adults who were
given high energy/protein liquid supplements gained weight and maintained
it as long as they suffered no other secondary infections. AIDS patients
in another study were given fish oil supplements containing omega-3 fatty
acids, which are required by the body to respond to inflammation. Those
patients who did not suffer from new secondary infections gained weight.
Finally, in a third study, patients who had already lost a significant
amount of weight and were given counseling and a supplement containing
amino acids and several antioxidant vitamins and minerals gained weight
and experienced an increase in muscle mass.
Slide 14
Studies in which single or multiple micronutrient supplements were
given to patients showed that these supplements improved the immune
system, reduced oxidative stress and reduced the risk of morbidity and
mortality.
Here is a summary of some studies that measured the effects of
different supplements.
Studies carried out in Tanzania and South Africa showed that Vitamin A
supplementation reduced diarrhea and mortality and improved several
indicators of immune status in HIV-infected children. Other studies of men
from the United States have shown that improving Vitamin B12 status
improves CD4 cell counts. One study with Canadian adults concluded that
supplementation with vitamins E and C reduces oxidative stress and HIV
viral load. Because vitamin E is fat soluble, supplementation in late
stage disease may not be effective because it is not absorbed well, as
shown in one Zambian study.
Slide 15
- In France, HIV-infected patients were given selenium and
beta-carotene supplements which increased antioxidant enzyme functions
in those studied.
- A study of AIDS patients in Italy found that zinc supplements
reduced the incidence of opportunistic infections, stabilized weight
and improved CD4 counts. Some US studies, however, suggest that
additional zinc intake is associated with faster HIV disease
progression.
- And finally, a study of US AIDS patients showed that treating anemia
by providing synthetic erythropoietin slowed HIV disease progression
and increased survival time.
Slide 16
Now we will turn our attention to the question, "How does
nutrition affect mother-to-child transmission of HIV?"
Slide 17
HIV is transmitted from mother to infant during pregnancy, childbirth,
and through breastfeeding. It is important to realize that not all infants
born to HIV-positive mothers become infected with the virus. Some mothers
and infants are at greater risk. It is also important to point out that it
is not possible to determine the precise point in time when the virus is
transmitted, whether it is late in pregnancy, during childbirth, or in the
early weeks of breastfeeding. For this reason, the risk of HIV
transmission attributable to these time periods is not exact. In the
absence of antiretroviral drugs and other obstetrical interventions, it is
estimated that 5-10% of HIV-infected mothers pass the virus to their
surviving newborns during pregnancy, and between 10 and 20% will pass the
virus during childbirth. In others words, about 20% of newborn infants
will be infected with HIV. Breastfeeding transmission depends on how long
the mother breastfeeds as well as other conditions, such as maternal
health, breast health and the young infants’ exposure to other foods,
liquids and pathogens. When practiced for about 2 years, between 10-20% of
babies not infected at birth will become infected with HIV through
breastfeeding.
UNAIDS estimates that 600,000 infants worldwide are infected with HIV
each year - 500,000 of these infants are in Africa.
Slide 18
There are several ways that the nutritional status of a mother may
influence her risk of transmitting HIV to her infant.
- Nutritional deficiencies impair the immune system and may lead to
more frequent and severe opportunistic infections in the mother.
Advanced clinical disease and immune system impairment are risk
factors for mother to child transmission.
- Some nutritional indicators, such as low serum retinol and selenium
levels, are associated with viral shedding in blood, breast milk and
lower genital tract secretions, increasing infant exposure to the
virus.
- Low birth weight and prematurity, which may result from nutritional
causes or from advanced HIV disease, are risk factors for
mother-to-child transmission.
- Malnutrition during pregnancy results in low fetal stores of some
nutrients. This may weaken the immune system and make the fetus or
newborn more vulnerable to HIV.
- And, malnutrition may impair the integrity of the placenta, the
lower genital mucosal barrier, and the gastrointestinal tract, and
weaken the mucosal immune system.
In each of these cases, HIV transmission could be facilitated.
Unfortunately, little is known about the actual impact of maternal
nutrition on HIV transmission.
Slide 19
Several studies have been carried out to explore whether daily,
antenatal vitamin A and beta-carotene supplementation or supplementation
with multivitamins can prevent HIV transmission during pregnancy and
childbirth.
These studies were conducted in Tanzania, where vitamin A or
multivitamins were provided, and in South Africa, Malawi and Zimbabwe,
where only vitamin A was given.
To date, none of the studies have shown a positive benefit of vitamin A
or multivitamins for reducing mother-to-child transmission during
pregnancy or childbirth. In the South African study, however, vitamin A
reduced mother-to-child transmission by 47% in a sub-group of infants born
at or before 37 weeks gestation.
The impact of daily vitamin A and multivitamin supplementation on HIV
transmission during breastfeeding is still being studied.
Slide 20
Although these studies did not show that nutrition supplementation
reduced HIV transmission, other benefits were observed in both the mothers
and newborns.
In the South Africa study, vitamin A supplementation reduced the risk
of preterm birth.
In Tanzania, daily multivitamin supplements improved maternal immune
status and reduced the risks of fetal death, low birth weight, small size
for gestational age and severe preterm delivery.
These findings suggest the importance of improved nutrition for
HIV-infected women during pregnancy and after delivery.
Slide 21
It is also important to consider that HIV-infected women are more
vulnerable to malnutrition than uninfected women during pregnancy.
The physiological changes that occur during pregnancy require the
mother to get extra nutrients for adequate gestational weight gain to
support the growth and development of the fetus. As already mentioned, HIV
infection increases energy, protein and other nutrient requirements. These
requirements are in addition to those needed to support a healthy
pregnancy and to prepare for breastfeeding.
Yet there are no published recommendations for dietary intake by
HIV-infected pregnant and lactating women.
In addition, studies suggest that HIV-infected women are more
vulnerable to anemia, particularly severe anemia, than uninfected women.
Anemia is a common problem during pregnancy that is made worse by the
presence of HIV.
Slide 22
The impact of breastfeeding on maternal HIV disease progression and
survival has not been adequately studied.
The increased nutritional demands of lactation may speed-up postpartum
weight loss, which is a risk factor for reduced survival in HIV-infection.
Two studies were published in the year 2001 documenting mortality in
breastfeeding versus non-breastfeeding mothers in Africa. Neither study
was originally designed to address this issue.
One study in Kenya found that HIV positive mothers who breastfed were
more likely to die in the 2 years following delivery when compared with
mothers who did not breastfeed. Another study in South Africa saw no
increased morbidity or mortality in breastfeeding women. The different
findings in these two studies may be due to differences in maternal
nutritional status.
In 2001, WHO released a statement saying that the evidence is not
conclusive on this issue. More research is required before making any
policy recommendations against breastfeeding for maternal survival.
Slide 23
Based on available evidence, we recommend the following approach for
providing nutrition support to HIV-positive women.
First, preventing HIV infection is very important. Then, if infection
occurs, preventing the malnutrition that accompanies it is just as
important. Preventing malnutrition can be done by promoting improved diet
and proper eating habits in youth. If a woman’s diet is not varied, then
she may need a multivitamin supplement.
It is especially important for programs to promote and support good
hygiene, sanitation and food safety practices for mothers and babies.
These topics are discussed in the Nutrition Care and Support tutorial.
Finally, nutrition support should be provided in the context of
holistic care, including supportive counseling as well as medical care to
address other issues affecting the health and well-being of HIV-infected
women and their families.
Slide 24
During pregnancy, HIV-positive women need special nutritional support
in addition to getting good antenatal care. It is important to do the
following:
- monitor the mother’s weight gain and counsel her about good
nutrition
- provide iron-folate supplements to prevent anemia
- provide daily multivitamin and other food supplements, if they are
available, to women who are not gaining adequate weight.
- prevent and treat infections, particularly those that affect food
consumption or increase the risk of HIV transmission and
- give antiretroviral drugs to reduce mother-to-child transmission, if
available.
All HIV-positive women should be fully informed about ways to reduce
the risk of transmitting HIV to their newborns, including all the infant
feeding options and risks. There are ways to make breastfeeding safer for
HIV-positive women if they decide to breastfeed. Likewise, if women choose
not to breastfeed, then there are options and risks that must be
discussed. If a woman is at risk of malnutrition and she is breastfeeding,
programs should consider providing nutritional support to prevent rapid
weight loss, as well as to enhance the success of exclusive breastfeeding.
Slide 25
In summary:
HIV affects nutrition in many ways. The impact begins early in the
course of HIV infection, even before other symptoms are observed.
Nutritional status also affects HIV-disease progression and mortality.
Improving and maintaining good nutrition may prolong health and delay
HIV-disease progression.
Slide 26
The impact of different nutrition interventions on HIV depends on the
type of intervention and the stage of HIV disease:
- Counseling and other interventions to prevent or reverse weight loss
are likely to have their greatest impact early in the course of HIV
infection.
- Nutritional supplements, particularly antioxidant vitamins and
minerals, may improve immune function and other HIV-related outcomes,
especially in nutritionally vulnerable populations.
Care must be taken, however, when giving supplements, especially during
pregnancy and breastfeeding. Excessive amounts of certain nutrients
(including vitamin A, vitamin E, zinc, and iron) impair rather than
improve the immune system and can cause harm to mother and infant.
HIV-positive women are at greater nutritional risk than uninfected women
during pregnancy and breastfeeding.
Meeting the nutrient and energy requirements of HIV-infected mothers
will improve both maternal and infant health.
