Effects of Malnutrition

KEY POINTS

Nutrition and Immunity: You Are What You Eat
Physiological and pharmacological effects of zinc on immune response. Titers of antibody to common pathogens: Copper levels are usually normal or elevated during serious illness or trauma in people with HIV. So, balanced nutrition and dietary consultation with experts helps in balancing immune effects, malnutrition, and HIV infection. Thus, it appears that zinc supplementation is clinically effective in reducing morbidity and mortality due to diarrhoeal disease and malaria in children.

1. Introduction

Journal of Immunology Research

The doctor will be able to conduct a physical exam and check for underlying conditions that lead to malnutrition. He will ask questions about the child's diet and eating habits. In addition, the doctor may also order blood tests, measure the child's body mass index, check height and weight and order other tests as deemed necessary.

If an underlying condition is causing the child's condition, the doctor will recommend ways to help combat the malnutrition, which may include a referral to a specialist. If the problem lies with the amount and type of food the child eats, a dietitian will come up with a food plan and may recommend vitamin and mineral supplements. The best way to treat malnutrition is to prevent it from occurring in the first place.

A balanced diet is needed to maintain good health. Consumption of a variety of foods will help you accomplish this goal.

The food groups in a healthy diet include proteins, fats, carbohydrates, dairy, fruit and vegetables. Last Updated 16 September, Overall Effects of Malnutrition 1. Body Mass Changes Lean body mass is naturally lost as you age but it can also be lost when you are malnourished.

Reduced Wound Healing If your body does not receive the nutrients it needs, it cannot properly heal itself. Severe Weight Loss Severe weight loss is also known as cachexia. Failure of Organs If you suffer from malnutrition, you have an increased risk of organ failure. Stress Malnutrition can lead to loss of concentration, memory and focus, which can result in increased stress.

Emotional Instability Some of the effects of malnutrition are behavioral. Effects of Malnutrition on Children Children suffering malnutrition can develop ailments, disorders and diseases that may affect them for the rest of their lives. Short-Term Implications Immune System: When children suffer from malnutrition, they also suffer from a weakened immune system.

The most definitive evidence that zinc deficiency is critical for immune function in humans comes from experimental zinc deficiency induced by dietary restriction in human volunteers NK cell activity was also reduced in the volunteers on a zinc-deficient diet.

In studies in iron-deficient humans, iron deficiency has been associated with defects in both adaptive and innate immunity, and these are reversible with iron therapy Adaptive immune defects include reduced T-cell numbers, reduced T-cell proliferation, reduced IL-2 production by T cells, reduced MIF production by macrophages, and reduced tuberculin skin reactivity.

Innate immune defects include reduced neutrophil killing, probably due to reduced myeloperoxidase activity and impaired NK cell activity. However, the picture is far from simple. Lactoferrin in human milk chelates iron and inhibits bacterial proliferation by depriving the bacteria of an essential nutrient. The bacteriostatic effect of human milk is abolished by iron therapy 86 , so that iron therapy would be expected to increase neonatal intestinal infectious disease.

In milk-drinking nomads, iron therapy was associated with an increase in Entamoeba histolytica infection, possibly due to saturation of the milk transferrin that overcomes the protective effect The same group had previously noted recrudescence of malaria and schistosomiasis in nomads treated with iron An overview of iron supplementation studies in malarious regions included 11 trials Five of nine trials in which clinical malaria was assessed showed a deleterious effect, and no trials showed benefit.

Respiratory infections and other infectious morbidity were also, if anything, increased though diarrhoeal disease was not. This deleterious effect of iron supplementation on infectious disease has not been observed in clinical trials in nonmalarious regions 85 , though there is evidence that dialysis and multiply transfused patients with iron overload have immune defects In summary, it is difficult to draw a firm conclusion as to whether iron status contributes to the impaired immunity to parasites seen in malnutrition.

There is evidence of T-cell and innate immune impairment in iron deficiency, but supplementation i. Selenium is an important antioxidant that has been shown to have wide-ranging immunostimulant effects in macrophages and T and B cells in humans However the evidence for this rests on a very small number of primary publications 93 , The most compelling recent evidence is an example of the sort of functional immunological testing that is all too rare in this field They also showed more rapid clearance of the virus from stool.

The situation is very similar for vitamin E, in which there is much interest, but for which the evidence base is narrow.

In one clear-cut study in elderly people, vitamin E supplementation for 4 months increased DTH responses and increased antibody titres to clinically relevant vaccines hepatitis B, tetanus but not immunoglobulin levels or T or B cell numbers There are no data to our knowledge of the effect of these micronutrients specifically on immune responses to parasites, but these data suggest that antioxidant nutrients are likely to be important in maintaining immunity.

There is evidence that malnutrition impairs elements of adaptive and innate immunity which would be important for defence against parasitic infections, although evidence of increased incidence or severity of parasitic infections in malnourished humans is fairly limited.

The evidence that this immune dysfunction is attributable to deficiency of protein or other macronutrients is weak; we find it unconvincing and conclude that it has been overstated in the past on the basis of poorly controlled studies. On the other hand, there is good evidence of links between micronutrient deficiencies and immune impairment. This evidence is strongest for zinc, deficiency of which leads to impairment of both innate and T-cell responses.

The evidence that antibody responses are impaired in any malnourished state is much less convincing. Given the very heavy burden of infectious disease around the world, and its massive contribution to illness and premature death, this field warrants much greater attention. As primary malnutrition is usually associated with famine, conflicts and population displacement, and confounding factors in secondary malnutrition are inevitable, observational studies are difficult to interpret.

Study of patients with anorexia nervosa could still give much useful information on the impact of macronutrient depletion. However, the most useful information will be derived from specific controlled interventions in volunteers and in patients. National Center for Biotechnology Information , U. Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2. Received Feb 2; Accepted May 8. This article has been cited by other articles in PMC.

Abstract KEY POINTS Clinical malnutrition is a heterogenous group of disorders including macronutrient deficiencies leading to body cell mass depletion and micronutrient deficiencies, and these often coexist with infectious and inflammatory processes and environmental problems. There is good evidence that specific micronutrients influence immunity, particularly zinc and vitamin A.

Iron may have both beneficial and deleterious effects depending on circumstances. There is surprisingly slender good evidence that immunity to parasites is dependent on macronutrient intake or body composition.

Increased incidence or severity of infections. It should be noted that without evidence of increased susceptibility to, or severity of, infectious disease, abnormalities in laboratory assessments do not constitute an immunodeficiency.

Markers of immunodeficiency laboratory or clinical, some of these are well validated, others much less so. Table 1 Evidence for elements of immunodeficiency in cases of malnutrition. Open in a separate window. Macronutrients Clinical trials of nutritional rehabilitation and immune function are few. Vitamin A It has been clear that vitamin A has important anti-infective properties since when it was shown that it reduced case fatality from measles. Zinc There is abundant clinical evidence that zinc is a critically important nutrient for the proper functioning of the immune system.

Iron In studies in iron-deficient humans, iron deficiency has been associated with defects in both adaptive and innate immunity, and these are reversible with iron therapy Other antioxidant molecules Selenium is an important antioxidant that has been shown to have wide-ranging immunostimulant effects in macrophages and T and B cells in humans Improved nutritional recovery on an elemental diet in Zambian children with persistent diarrhoea and malnutrition.

Naturally acquired immunity to Plasmodium falciparum malaria in Africa. Mannose-binding lectin is a disease modifier in clinical malaria and may function as opsonin for Plasmodium falciparum -infected erythrocytes. Helminth antigens modulate TLR-initiated dendritic cell activation. Toll-like receptor 9 mediates innate immune activation by the malaria pigment hemozoin.

Sacks D, Sher A. Evasion of innate immunity by parasitic protozoa. The road less travelled by: Host cell-mediated responses to infection with Cryptosporidium. An immunological assessment of patients with anorexia nervosa.

Am J Clin Nutr. Cytokine production in anorexia nervosa. Immunodeficiency associated with anorexia nervosa is secondary and improves after refeeding.

Basic Clin Pharmacol Toxicol. Nutrition and immune function in HIV infection. Albendazole chemotherapy for AIDS-related diarrhoea in Zambia — clinical, parasitological and mucosal responses. Improved survival by home total parenteral nutrition in AIDS patients: Fatal infections in protein-calorie malnourished children with thymolymphatic atrophy. A host determinant for Pneumocystis carinii infection.

Am J Dis Child. Shimeles D, Lulseged S. Clinical profile and pattern of infection in Ethiopian children with severe protein-energy malnutrition. East Afr Med J. Malnutrition cell-mediated immune deficiency and acute upper respiratory infections in rural Bangladeshi children.

Nutritional status and risk of infection among Ethiopian children. Undernutrition as an underlying cause of malaria morbidity and mortality in children less than 5 years old.

Am J Trop Med Hyg. Diet and cerebral malaria: New perspectives on a subclincial form of visceral leishmaniasis. Thymolymphatic deficiency and depression of cell-mediated immunity in protein-calorie malnutrition. In vitr o lymphocyte-differentiating effects of thymulin Zn-FTS on lymphocyte subpopulations of severely malnourished children. Development of impaired cell-mediated immunity in mild and moderate malnutrition. Leucocyte function in children with kwashiorkor. Cell-mediated immune responses in malnourished host.

A study of some changes of cell-mediated immunity in protein energy malnutrition. J Egypt Soc Parasitol. Nutrition immunity and infections: T lymphocyte subpopulations in protein-energy malnutrition. Flow cytometry study of lymphocyte subsets in malnourished children and well-nourished children with bacterial infections. Clin Diagn Lab Immunol.

Immunoglobulins and antibody response in children with protein-calorie malnutrition. Impact of nutritional status on antibody responses to different vaccines in undernourished Gambian children. Nutrition Immunity and Infection: Secretory IgA in protein-calorie malnutrition.

Secretory IgA synthesis in Kwashiorkor. J Clin Lab Immunol. Acute-phase protein response is impaired in severely malnourished children. Clin Sci Lond ; Acute-phase protein response to infection in severe malnutrition. The acute-phase protein response to infection in edematous and nonedematous protein-energy malnutrition. Complement and C3-proactivator levels in children with protein-calorie malnutrition and effect of dietary treatment. Metabolic and bactericidal activities of leucocytes in protein-calorie malnutrition.

Effect of renutrition on natural and cell-mediated immune response in infants with severe malnutrition. J Paediatr Gastroenterol Nutr. Seth V, Chandra RK. Opsonic activity phagocytosis and bactericidal capacity of polymorphs in undernutrition. HIV accounts for significant immunosuppression in an infected individual. If the corroboratory indices of good health are satisfactory, the suppression of immune defences can be mitigated.

One such index is nutrition. HIV, immune expression, and nutrition interactions are complex and related to each other. Nutrition and HIV are strongly related and complement each other. A malnourished person after acquiring HIV is likely to progress faster to AIDS, because his body is weak to fight infection whereas a well-nourished person can fight the illness better. It has been proved that good nutrition increases resistance to infection and disease, improves energy, and thus makes a person stronger and more productive.

Nutritional improvement measures must be initiated before a patient reaches this stage. One of the factors responsible for malnutrition in an HIV-infected person is reduced appetite, which could be due to difficulty in ingesting food as a result of infections like oral thrush or oesophagitis caused by Candida, a common opportunistic infection in HIV-infected people and fever, side effects of medicines, or depression.

Poor absorption of nutrients may be due to accompanying diarrhea which may be because of bacterial infections like Salmonella or Mycobacterium avium intercellular ; viral like CMV or parasitic infections like Giardia, C. Gastrointestinal tract is the largest lymphoid organ in the body and is directly affected by HIV infection. HIV causes damage to the intestinal cells by causing villus flattening and decreased D-xylose absorption.

This leads to carbohydrate and fat malabsorption thereby affecting fat soluble vitamins like vitamins A and E, which are important for proper functioning of immune system. Whereas larger amounts of nutrients are required during fever and infections that accompany an HIV infection, they are utilised poorly by the body.

This leads to loss of weight and lean muscle tissue, further causing damage to the immune system. Lack of iron in the diet and infections such as malaria and hookworm lead to anaemia.

Anaemia causes lethargy, further reduces food intake and nutrient absorption, and also causes disruption of metabolism, chronic infections, muscle wasting, or loss in lean body tissue [ 4 ]. AIDS-related dementia or neuropsychiatric impairment may make the patients unable to care for themselves, forget to eat, or unable to prepare balanced meals.

Even in households with HIV-infected members, nutritional impacts can be seen if the infected adult becomes too sick to work and provide food for themselves and their families [ 5 , 6 ]. Dietary intake also varies inversely with level of virus, suggesting that viral replication directly or indirectly suppresses appetite [ 7 ].

Malnutrition is frequent and is considered a marker for poor prognosis among HIV-infected subjects [ 8 ]. Also, in acute viral infections such responses could be seen but they were generally not present in patients with chronic progressive infections. Antiviral immunity involves both the arms of the immune system. The protective component of cell-mediated immunity involves the cytotoxic CD8 T-lymphocytes.

Schmitz and colleagues had demonstrated the effects of CD8 T lymphocytes in monkeys experimentally infected with simian immunodeficiency virus SIV.

Humoral immunity to HIV is expressed by neutralising antibodies. Anti-HIV antibodies are able to bind cell-free virus and potentially prevent established infection in the challenged host.

Neutralising antibodies attaching to CD4 binding site of HIV have been identified which appear to prevent the virus from attaching to and infecting T cells. Though HIV-specific humoral immune responses can be detected during primary infection, they mostly comprise low-avidity env specific IgG antibodies with little or no neutralising activity [ 12 ]. Significant neutralising titers are believed to take place after chronicity has set in.

HIV evolves various strategies to establish chronicity in human body. Initial CTL responses cause downregulation of viremia and prevent disease progression, but later it induces the selection of virus mutants capable of escaping the immune response [ 14 ].

Immune activation in HIV is supported by an experiment by Pandrea et al. High T-cell turnover in chronic HIV infection is attributed to overlapping and nonsynchronized bursts of proliferation, differentiation, and death in response to T-cell receptor- TCR- mediated stimulation and inflammation [ 16 , 17 ]. Antiretroviral therapy ART results in a marked reduction of T-cell activation and apoptosis and helps to decrease naive T-cell consumption and restore their numbers [ 18 ].

Chronic HIV infection also causes immunological or direct virotoxic effects on gastrointestinal tract which shows blunted villi, crypt hyperplasia, and damaged epithelial barrier with increased permeability and malabsorption of bile acid and vitamin B12, microbial translocation, and enterocyte apoptosis. There is a decrease of luminal defensins and massive CD4 T-cell depletion but high concentration of infected CD4 T cells [ 19 ].

Malnutrition is considered to be the most common cause of immunodeficiency worldwide [ 20 ]. Malnutrition, immune system, and infectious diseases are interlocked in a complex negative cascade [ 1 ]. Malnutrition elicits dysfunctions in the immune system and promotes increased vulnerability of the host to infections [ 21 ]. Every type of immunological deficiency induced by malnutrition can be included under the NAIDS umbrella.

Protein-energy malnutrition PEM , now known as protein-energy undernutrition, is an energy deficit due to chronic deficiency of all macronutrients [ 22 ]. In children, PEM causes widespread atrophy of lymphoid tissues, particularly T-lymphocyte areas.

The thymus involutes causing a reduction in the thymus-derived lymphocyte growth and maturation factors, arrest of lymphocyte development, reduced numbers of circulating mature CD4 helper cells, and impairment of antibody production to T-dependent antigens.

Imbalance in Th1-Th2 activation occurs depending on nature of stimuli and altered regulatory pathways, including responses mediated by the nuclear factor-kB NF-kB [ 23 ], a major transcription factor involved in the development of innate and adaptive immunity.

However, CD8 suppressor cells are relatively preserved. The lymphocytes not only get reduced in blood, but also impaired show T-lymphocyte mitogenesis and diminished activity in response to mitogens [ 24 ]. According to Chandra [ 25 ], in children with PEM, there is a decrease or reversal of the T-helper-suppressor cell ratio and total numbers of T-lymphocytes decrease due to reduced numbers of these T-cell subpopulations.

In malnourished children, changes such as dermal anergy, loss of delayed dermal hypersensitivity DDH reactions, and loss of the ability of killer lymphocytes to recognize and destroy foreign tissues were noted [ 20 ]. Necropsy studies on malnourished patients have also shown profound depletion of the thymolymphatic system and severe depression of cell-mediated immunity.

Chronic thymic atrophy with peripheral lymphoid tissue wasting along with depletion of paracortical cells and loss of germinal centres was noted. This was suggested to have led to various types of infections from which these patients actually died [ 26 ].

HIV and Malnutrition: Effects on Immune System