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Vitamin A (which is retinol) and immunity

WHO report
https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON494

https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-a/

Vitamin A has several important functions

helping natural defence against illness and infection (immune system) work properly

helping vision in dim light

keeping skin and the lining of some parts of the body, such as the nose, healthy

Good sources of vitamin A

Good sources of vitamin A (retinol) include:

cheese

eggs

oily fish

fortified low-fat spreads

milk and yoghurt

liver and liver pâté

If you're pregnant you should avoid eating liver or liver products, (NHS, 2023)

Excess vitamin A is toxic.

Vitamin A deficiency

https://www.who.int/data/nutrition/nlis/info/vitamin-a-deficiency

What are the consequences and implications?

Night blindness is one of the first signs of vitamin A deficiency.

In its more severe forms, vitamin A deficiency contributes to blindness by making the cornea very dry, thus damaging the retina and cornea.

An estimated 250 000–500 000 children who are vitamin A-deficient become blind every year,

and half of them die within 12 months of losing their sight.

World’s leading preventable cause of childhood blindness.

Deficiency of vitamin A is associated with significant morbidity and mortality from common childhood infections,

Vitamin A deficiency also contributes to maternal mortality and other poor outcomes of pregnancy and lactation.

It also diminishes the ability to fight infections.

Even mild, subclinical deficiency can be a problem, because it may increase children's risk for respiratory and diarrhoeal infections,

decrease growth rates,

slow bone development and decrease the likelihood of survival from serious illness.

Beta carotene

Red-orange pigment, in plants and fruits,

especially carrots and colourful vegetables.

The body converts beta carotene into vitamin A

The advantage of dietary beta carotene is that the body only converts as much as it needs.

Healthy antioxidant

May prevent cognitive decline
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/769551

May help lung function
https://thorax.bmj.com/content/61/4/320

Both may be due to preventing oxidative stress
https://www.medicalnewstoday.com/articles/252758#_noHeaderPrefixedContent

Foods rich in beta carotene:

Apricots, Asparagus, Broccoli, Carrots, Chives, Dandelion leaves, Grapefruit, (Chilli powder, oregano, paprika, parsley), Kale,
Onions, Peas, Peppers, Plums, Pumpkin, Spinach, Squash, Sweet potatoes.

Role of Vitamin A in the Immune System
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162863/

Needed for mucous membrane innate immunity (respiratory and GI)

Essential for the normal function of many immune cells such as T lymphocytes

Vitamin A deficiency is associated with severe Mycoplasma pneumoniae pneumonia in children

https://www.youtube.com/redirect?event=comments&redir_token=QUFFLUhqbnZodGdTajdHbllOaTVLWmVFTE9pcFcyWXlCZ3xBQ3Jtc0trbzNvb18yUzUxWUZkZDNEdVdqLTRmOF9qRDA4Q3ItZFFZTEV3b251U25lM3BGblpFR1huMHo5dldCU2E2Y09fQUx6cms5ODNxWGNFbDVRVWlrNTR6RHdibUNJMldhMHdZY2xPdFgxbWFjdXQ3aUNqTQ&q=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC7049042%2F&stzid=Ugwx9s13s_uXnqgTv7B4AaABAg

Beijing, Feb, 2020

N = 122 children, (0 – 15)

52 sMPP

Severe Mycoplasma pneumoniae pneumonia

70 nsMPP

Non-severe Mycoplasma pneumoniae pneumonia

Serum levels of vitamins A, D, and E were measured and compared, and correlated with nsMPP and sMPP.

Results

The age was older in the sMPP samples than that in the nsMPP samples.

(7.12 vs. 4.01)

So older children suffered more severe infections.

Vitamin A deficiency was present in both the nsMPP and sMPP samples.

Vitamin A levels were significantly lower in the sMPP serum than that in the nsMPP serum.

(0.15 vs. 0.19)

Vitamin A deficiency was defined

Deficiency, <0.2 mg/L,

Subclinical vitamin A deficiency, 0.2–0.3 mg/L

Normal vitamin A level by 0.3–0.7 mg/L.

So, children with lower vitamin A levels suffered more severe infections.

Vitamins E and D levels were also lower in sMPP children

Vitamin E (7.4 vs. 8.22)

Vitamin D (23.08 vs. 32.07)

Both sMPP and nsMPP did not show a deficiency of vitamins E and D.

Vitamin A deficiency OR 0.001 – 0.334, (P=0.009) associated with sMPP

Incidence of vitamin A deficiency

Vitamin A deficiency in under 6 years was 85% of children

Vitamin A deficiency in over 6 years was 62.5% of children

Vitamin A supplementation could reduce the incidence of sMPP.

Conclusions

Vitamin A deficiency is associated with sMPP and more likely present in the younger sMPP children.

Therefore, it is important to monitor and supplement vitamin A in Mycoplasma pneumonia patients.

Extra details

Mycoplasma pneumoniae (MP) frequently causes community-acquired pneumonia in children

Occurs throughout the year.

Can be transmitted by droplets

Children of all ages are susceptible

In recent years, the number of children with MP pneumonia has increased,

and they have a prolonged course of the disease.

Typical symptoms

Fever, wheezing, difficulty in breathing, chest pain, and chills.

MPP, particularly refractory or severe MPP, often result in pleural effusion, atelectasis, and another organ damage.

Vitamin deficiencies lead to a higher incidence of respiratory
and digestive diseases in patients, particularly in children.

Vitamins also have a significant impact on disease prognosis.

Our findings show that vitamin A deficiency was significantly correlated with sMPP, and more likely occurred in the younger children.

Vitamin A plays an important pleiotropic role in supporting the normal mucosal barrier,

with the result of the increase of the risk of invasive pathogens.

Children who presented vitamin A deficiency were more likely to get an acute respiratory tract infection and diarrhea.

Vitamin A regulates cytokine

The functions of macrophages, neutrophils and natural killer cells were impaired,

and the protective function of the respiratory mucosa was also decreased in the deficiency of vitamin A.

Vitamin A deficiency can lead to changes in the extracellular matrix and basement membrane protein content and distribution.

Vitamin A deficient rats have thicker alveolar basement membranes

The incidence and severity of infectious diseases are increased in vitamin A deficient children.

Epidemiological surveys show that the incidence of vitamin A deficiency is significantly associated with age;

the younger the age, the higher the incidence of vitamin A deficiency.

Vitamin A deficiency was associated with sMPP, and the supplementation of vitamin A may reduce the occurrence of sMPP in children.

Several studies also showed that supplementation of vitamin A could reduce the incidence of respiratory infections and shorten the course of the disease.

Vitamin A deficiency was more likely present in younger sMPP children,

suggesting that supplementation of vitamin A is more important in younger children who have potential MP infection.

In our study, although we did not find a significant correlation between vitamins E and D levels with nsMPP and sMPP, vitamins E and D should be maintained at least at the normal levels.

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