Zinc is an essential nutrient that plays many important roles in the body. It is ‘essential’ because the body cannot produce zinc on its own, and thus, it should be obtained through food sources.  

After iron, zinc is the most abundant trace mineral (minerals required in small quantities) in the body.

Zinc boosts the immune system and is important for metabolic function. 

It is well known for its role in wound healing and the sense of taste and smell. 

It is a part of many enzymes that are required for sending messages across cells in the body. 

An Interesting Note About Zinc Consumption

Zinc absorption from the diet depends on the total amount of zinc present in the food.  

It has been found that the more the amount of zinc present in food, the lower the amount absorbed. 

This means that zinc is better absorbed when taken in small doses.  

Why Is Zinc Important For Us?

Zinc plays an important role in the functioning of immune cells. So a deficiency in this nutrient can lead to a weakened immune response. 

Zinc is present in the part of the cell where the formation of DNA and proteins occur. Protein production from DNA is a multi-step process, where zinc plays an important role in each step.

Gene expression is the process where the information in the gene is used to produce proteins and other gene products. Zinc plays a role in regulating how much protein or product is produced by the genes. 

Zinc plays a role in the activity of more than 300 enzymes. The ‘zinc-binding’ sites help one compound attach to another in chemical reactions.

Zinc supports normal growth and development during pregnancy, infancy, and adolescence. According to a study, infants with low birth weight saw significant weight gain improvements when supplemented with zinc.

Zinc has anti-inflammatory properties - the ability to reduce inflammation or swelling. So, it can help with skin problems like acne and rashes.

What Are The Different Forms Of Zinc?

Zinc is available as supplements in various forms, each of which impacts health in different ways. 

Zinc sulfate is the least expensive form available; however, it is also the least absorbed by the body. This form is used for acne treatment.

Other forms of zinc include:

  1. Zinc Gluconate: It is a commonly available form and is used in many cold medications and nasal sprays
  2. Zinc Picolinate: It is easily absorbed and dissolved - more readily than the other forms - in the body to release zinc
  3. Zinc Citrate: This form of zinc supposedly tastes better than the other forms
  4. Zinc Acetate: Like gluconate, this is also commonly used in cold and flu medications 

The Story Behind Zinc Requirements

Though the importance of zinc in humans was established only in the 1960s, its impact on agricultural production was identified in 1869 itself, when zinc was reported as an important nutrient for the growth of a fungus, Aspergillus niger. In 1914, it was discovered that maize, a common crop, also required zinc for normal growth. By the 1920s, it was established that zinc is needed for the growth of all higher plants.

The years from 1920 to 1950 witnessed the essentiality of zinc in mice, poultry, and swine. However, researchers were still skeptical about the possibility of zinc deficiency in humans. This ended when the first case of zinc-deficiency-induced dwarfism that resulted in delayed sexual maturation was reported in the United States. Subsequent zinc supplementation resulted in improved growth and development. 

In 1974, the National Research Council of the National Academy of Sciences declared zinc as an essential element for humans, and in 1978, FDA mandated the inclusion of zinc in prenatal supplements.

In the developing world, nearly 2 billion people may be affected by zinc deficiency. Consumption of cereal proteins high in phytate was identified as the major culprit for this. Phytate/phytic acid is a natural substance found in plant seeds. It is known for impairing the absorption of various minerals like iron and zinc. 

What Is The Recommended Daily Intake Of Zinc?

The recommended daily intake (RDI) for adults varies between 8 to 11mg. The maximum tolerable amount is 40mg per day.

Genetics of Zinc Requirements

Several proteins, called the zinc transporters are responsible for the circulation and absorption of zinc in the body. Zinc homeostasis (ability to maintain stable levels of zinc) is managed by zinc intake and output transporters that are coded by SLC30A and SLC39A gene families. 

SLC39A4 

SLC39A4 codes for zinc transporter ZIP4, which is responsible for the absorption of zinc in the intestines. Differences in the SLC39A4 can alter the structure of the ZIP4 protein and hence affect zinc absorption. Certain types of SLC39A4 gene are associated with lower zinc levels.

SLC30A2

SLC30A2 codes for zinc transporter 2 or the ZNT2 protein. This gene plays a role in neonatal (newborn) zinc deficiency. A type of this gene produces an ‘incomplete’ ZNT2 protein that results in the poor secretion of zinc into the breast milk. Infants that feed on this zinc-deficient breast milk go on to develop zinc deficiency in their later years. Two SNPs of SLC30A2, rs35235055 - also known as c.68T>C - and rs35623192 - also known as c.1018C>T - play a role in lower zinc secretion in breast milk.

SLC30A8

SLC30A8 codes for zinc transporter 8 or the ZNT8 protein. This protein is responsible for transporting zinc inside insulin cells, thereby promoting insulin release. Differences in the SLC30A8 can affect zinc transport. A certain type of this gene plays a role in increasing the risk of diabetes by reducing zinc transport and decreasing insulin secretion. A study on this gene also concluded that zinc supplementation could fix the error in glucose breakdown (by promoting insulin secretion), thereby treating diabetes.

SLC30A8 SNP rs13266634 is associated with the risk of type 2 diabetes. The CC type was found to have the lowest concentrations of zinc. Further, it was noted that zinc supplementation in people having the C type reduced the blood sugar levels.

The same study claimed that “Zinc intake has a stronger inverse association with fasting glucose concentration in individuals carrying the glucose-raising A allele of another SNP rs11558471 (in SLC30A8 gene.)” This meant that as zinc intake increased, a reduction in blood glucose levels was seen.

SLC30A3SLC30A3 codes for zinc transporter 3 or the ZNT3 protein. This protein is required for the transport of zinc into synapses, which are the site of electronic signalling between two nerve cells.

rs11126936 is an SNP in the SLC30A3 gene. A study found that individuals having TT and TG types had higher levels of zinc levels than those with GG.Previously, another SNP rs73924411 in the same gene was found to play a role in regulating zinc levels in people with cognitive impairment.

IL6

White blood cells express cytokines. Cytokines are a group of proteins that are expressed by the immune system. They play an important role in cellular communication, especially during immune responses. 

Some of these cytokines are termed as interleukins - abbreviated as IL. IL6 or interleukin 6 is a cytokine that is produced at the site of inflammation. The IL6 gene encodes IL6 protein. This is mainly responsible for the acute phase response (a response that is raised immediately after an injury/infection). 

It also has an anti-inflammatory myokine role. Myokine responses are essentially cytokine responses that occur due to muscle contraction. 

Evidence suggests that IL6 can be used as an 'inflammatory marker' for COVID-19 prognosis -meaning, higher levels of IL6 are linked to a high fatality rate of COVID-19. 

The levels of IL6 are related to the zinc levels in our bodies. 

The relationship between the IL6 gene and zinc levels is reciprocal.

When there’s a zinc deficiency, it affects the IL6 gene, increasing IL6 cytokine production, which lowers zinc levels even further. 

rs1800795

Also known as 174 G/C, rs1800795 affects the zinc levels upon dietary consumption of zinc. A study on the European population revealed that people having the GG type of rs1800975 had higher levels of IL6 (and hence, lower levels of zinc) than those with CC type.

What Are The Symptoms Of Zinc Deficiency?

According to the World Health Organization (WHO), about one-third of the world’s population suffers from zinc deficiency. 

The symptoms of zinc deficiency include:

What Are The Symptoms Of Having Excess Zinc In The System?

The tolerable upper intake level (UL) - the maximum amount of nutrient intake that is likely to be not risky for health - for zinc is 40 mg per day for healthy adults. Excessive intake of zinc can lead to zinc toxicity.

Although there are no reported zinc toxicity cases from food sources, some zinc supplementation at incorrect doses could cause a problem. 

 Zinc toxicity can result in the following symptoms:

How You Can Test Your Zinc Levels

Zinc levels can be determined using a simple blood plasma test or a urine and hair analysis, since zinc is distributed throughout the body. 

However, it is difficult to identify zinc levels using laboratory tests alone. 

Doctors may assess other risk factors, including genetics and dietary intake, along with blood test results to identify your zinc requirements.

What Are The Health Benefits Of Zinc?

Zinc Helps Boost Immunity

Zinc is important for the growth and development of immune cells, namely the T-cells and B-cells. It also plays a role in immune responses that require antibody production.

Zinc ions exhibit antimicrobial activity and are necessary for the functioning of natural killer cells (another type of immune cells)

Acrodermatitis enteropathica, a rare disease, is associated with zinc deficiency. This condition increases the risk of viral, fungal, and bacterial infections.

The zinc requirements for women increase during pregnancy. Its deficiency can be harmful to the growing fetus.

A study conducted on mice showed that gestational (during pregnancy) zinc deficiency affected the offsprings' immune function, which persisted for three generations.

Zinc Can Help Preserve Bone Health

Zinc helps the formation of cells that are required for bone building. It also slows down the excessive degradation of bones. 

Zinc forms a part of many enzymes that are necessary to hold the structure of bones in place.

According to a study, excess zinc excretion plays a role in the development of osteoporosis.

Zinc Aids The Maintenance Of Healthy Hair And Skin

Hair loss in patches is often seen in people with zinc deficiency. This is because zinc plays an important role in a process that leads to the formation of hair follicles. 

Collagen is an important protein that gives structure to the skin and protects it against different strains. Zinc is a crucial component of collagenases, the enzymes that form collagen. According to a study, zinc supplementation can help slow down the degradation of collagen.

Zinc Can Reduce The Risk Of Certain Diseases

The progression of age-related diseases like macular degeneration can be prevented/delayed using zinc supplements.

Since zinc boosts immune function, it also helps prevent infection in older people. In fact, according to a study, people with adequate zinc levels had a 50% lesser risk of developing pneumonia compared to those who had lower levels. 

Non-Genetic Factors Influencing Zinc Levels

Zinc deficiency could also occur in people with the following conditions:

  1. Crohn’s disease or similar gastrointestinal diseases
  2. Sickle cell anemia
  3. Chronic kidney disease
  4. Pregnant and breastfeeding women
  5. Vegetarians and vegans
  6. Alcohol addictions
  7. Poor absorption of protein-energy
  8. Intestinal parasites or protozoal infection
  9. Pancreatic insufficiency - leads to poor absorption in intestines

What Are The Dietary Sources of Zinc?

Zinc is not stored in the body, so it must be included in the diet to ensure sufficient amounts are available. A healthy and balanced diet, which includes zinc-rich foods, will ensure sufficient vitamin and nutrient intake.

Animal Sources

  1. Oysters: Shellfish, in general, are healthy, low-calorie sources of zinc. Per 100 grams, oysters provide 61 mg of zinc. 
  2. Red meat: 100g of red meat contains around 4.8 mg of zinc, which is around 44% of the RDA.
  3. Eggs: With one big egg, you can meet 5% of the RDA for zinc.

Plant Sources

  1. Soy products: Food sources derived from soy like tofu, legumes can help you meet 12-15% of the RDA for zinc.
  2. Seeds: Although most seeds are packed with nutrients, some are better sources of zinc than the other. Hemp seeds, in particular, contain 3 mg of zinc per ounce.
  3. Nuts: Cashews, almonds, peanuts, and pine nuts don’t just boost zinc levels but are also rich in healthy fats and fiber.

Summary

Zinc is a trace mineral that is important for its role in immune function, growth and development, and protein production. The role of zinc in human health was only identified in the 1960s, and since then, the FDA has made it mandatory to include it in all prenatal products. The SLC gene family codes for proteins that are responsible for zinc transport and absorption in the body. Studies have shown that rs13266634 in the SLC30A8 gene plays a role in zinc transport into insulin cells. Individuals who have the CC type have decreased transport of zinc to the insulin cells. This results in lowered secretion of insulin, and hence a higher risk  for type 2 diabetes. rs35235055 and rs35623192 are two SNPs in SLC30A2 gene that are important for transport of zinc to the breast milk. Lower levels of zinc in breast milk can increase the risk for neonatal zinc deficiency. The recommended daily intake (RDI) for adults varies between 8 to 11mg, with maximum tolerable amount being 40mg per day. Oysters are an excellent source of zinc with one serving providing over 600% of the RDI. Some plant based food sources rich in zinc are tofu, legumes, hemp seeds, and nuts. 

References

  1. https://www.hsph.harvard.edu/nutritionsource/zinc/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4877790/
  3. https://pubmed.ncbi.nlm.nih.gov/29193602/
  4. https://academic.oup.com/advances/article/3/6/783/4557955
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3649098/
  6. https://www.nature.com/articles/pr2016108?proof=t
  7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3896616/
  8. https://www.mdpi.com/2072-6643/9/2/148/htm
  9. https://www.sciencedirect.com/science/article/abs/pii/S1344622317303565
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3896616/
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7129451/
  12. https://pubmed.ncbi.nlm.nih.gov/28218639/
  13. https://www.who.int/whr/2002/chapter4/en/index3.html

Selenium (Se) is an essential micronutrient (nutrients needed by the body in small quantities). It is required for its role in antioxidant activity, immunity, and thyroid function. 

The natural forms of this nutrient in our body are selenocysteine and selenoproteins. Humans are known to have 25 selenoproteins, with selenoprotein P and glutathione peroxidase (GPx) among the most studied. Most of the selenoproteins found in the body play a role in antioxidant function. 

Importance Of Selenium

Most of the selenoproteins found in the body play a role in antioxidant function. 

Some other important functions of selenoproteins include: 

The inorganic (chemically-derived) forms of selenium are available as selenide, selenite, and selenium. Selenium is taken up from the soil by plants, so dietary levels depend upon the soil's selenium content.

The Story Behind Selenium Needs

From an evolutionary point of view, humans adapted to selenium needs based on their geographical location. During early human migration, they inhabited areas with differences in the soil levels of certain micronutrients, like selenium.

Over the years, the body learned to adapt itself to the selenium availability in the soil. Thus, the soil concentration, along with the dietary practices of different populations, brought about the differences in the selenium requirements.

While selenium is very important for its function as a selenoprotein, it was essential to regulate blood levels of selenium to reduce the risk of selenium toxicity in areas with high environmental selenium levels.

 Some types of genes involved in selenium uptake and metabolism helped adapt to the environmental levels of selenium. For example, in regions with low selenium levels in the soil, people with higher/better absorption of selenium from the diet may have had a survival advantage.

On the other hand, regions of high selenium levels, people with lower absorption levels may have had an advantage.  

The RDA Of Selenium

The RDA of selenium for a healthy adult is 55 µg/ day, while the normal blood levels are between 70 to 150 ng/mL.

Genetics And Selenium Levels

CBS Gene

The CBS gene carries the instructions to make the enzyme cystathionine beta-synthase. This enzyme is responsible for converting a harmful amino acid, homocysteine, to another amino acid, cysteine, which is safe for the body. 

Some changes to the CBS gene play a role in the build-up of homocysteine in the body, causing many negative health implications.

It also leads to lower selenium levels in the body. 

According to a study, selenium levels are inversely associated with homocysteine levels - higher levels of homocysteine in the body lead to lower selenium levels.

Thus, the changes in the CBS gene that bring about the buildup of homocysteine can also cause selenium deficiency. 

rs6586282

rs6586282 is located on the CBS gene and regulates serum homocysteine and selenium levels. 85% of the people have a normal type of the CBS gene, while 15% have the type that could put them at risk for selenium deficiency. The T allele affects the clearance of homocysteine and causes its build-up, and is hence associated with lower levels of selenium in the body.

Symptoms Of Selenium Deficiency

The amount of selenium present in food sources is largely influenced by soil quality and other factors like rainfall and evaporation. 

Selenium deficiency can result in several health issues like:

Effects Of Excess Selenium 

Selenium toxicity: While selenium supplementation is very important for people with selenium deficiency, excess selenium can lead to a condition known as selenium toxicity. The safer upper limit for selenium is 400 micrograms a day for healthy adults. Anything above that could lead to toxicity, characterized by symptoms like fatigue, discoloration of the nail, brittleness, irritability, and garlic breath. Long-term or chronic toxicity can lead to loss of fertility and hypothyroidism.

Is There A Test To Identify Selenium Levels?

Selenium deficiency can be assessed by a qualified healthcare practitioner based on symptoms. Levels of the enzyme glutathione peroxidase may also be tested. This enzyme is known to play a role in selenium functioning. Low levels of the enzyme indicate low levels of selenium.  

What Are The Health Benefits Of Selenium?

Selenium Can Protect Against Respiratory Infections


An infection by a virus is known to increase reactive oxygen species or ROS and lower antioxidant enzyme levels in the body. Reactive oxygen species are molecules containing oxygen, which react with other molecules in the body cells. This could lead to oxidative stress damage,  resulting in increased viral replication. 


Selenium increases type 1 immunity against viral infections and restricts viral mutations. Viruses undergo changes to adapt to the human body better and escape any treatment against it.  

Identifying people at risk of selenium deficiency and supplementing their need may help in its use as adjuvant therapy (an add-on therapy other than the primary treatment) to treat viral infections.

Selenium Can Help Relieve Symptoms Of Respiratory Disorders

RSV or respiratory syncytial virus is a type of virus that causes respiratory infection with cold or flu-like symptoms. A study conducted on 75 children with respiratory diseases due to RSV showed the selenium supplementation helped relieve the symptoms faster.


Selenium Can Help Reduce HIV And SARS-COV-II Viral Particles

study conducted on people who tested positive for HIV showed that supplementation with selenium resulted in a reduced number of viral particles and an increase in T-immune cells

Recent research also found an association between selenium supplementation and SARS-COV-II viral multiplication.

Selenium Can Help Improve Cognitive Function

Selenium influences the chemicals that are known to play an important role in affecting mood and behavior in animals and humans. Thus, this nutrient is required for the brain's normal functioning. Selenoprotein P (SELENOP) plays a role in the transport of this trace mineral in the body.  


Selenium supplementation plays a role in improving mood-related issues. In a study conducted by Benton and Cook, 100mcg of selenium was given to the study population, while controls were given a placebo. The study found that supplementation with selenium resulted in an improvement in the mood. 


In another study by Gosney et al., micronutrient supplementation and its effect on the mood of nursing home residents were studied. Eight weeks after supplementation with 60 mcg of selenium, there was a reduction in depression scores.  

As selenium affects cognitive function, a deficiency in selenium levels can play a role in memory problems, lack of mental acuity (sharpness), or (in non-clinical terms) brain fog

Selenium Can Help Reduce Preeclampsia Risk

Preeclampsia is a condition in which pregnant mothers have high blood pressure, potentially affecting their pregnancy. A study on nearly 500 women showed that supplementation with selenium resulted in a 72% reduction in preeclampsia risk compared with controls. 

Selenium Can Help With Psychomotor Development In Children

A study conducted on mother and child to understand the impact of selenium on psychomotor function (the relationship between physical actions and cognitive function) showed that maternal selenium levels during the first trimester (in pregnancy) play a role in motor development during the child's first year.

The same study showed that the level of selenium in cord blood (blood in the tube that connects the mother to the baby) had a positive relationship with the child's language development at two years.

Non-genetic Factors Influencing Selenium Levels

The selenium levels in the food are influenced by selenium levels in the soil. Soil selenium levels may be affected by pH, rainfall, and evaporation. People with the following conditions may have lower selenium levels:

Dietary Sources of Selenium

The primary step towards adequate levels of selenium is to eat foods rich in selenium. The National Institute of Health recommends that 55µg of selenium should be consumed every day by people over the age of 14. 

Animal Sources of Selenium

  1. Fish: Yellowfin tuna is an excellent source of selenium, containing about 92 mcg per 3 ounces.
  2. Red meat: Pork, ham, and beef provide around 35-45 mcg of selenium for every 3 ounces of the meat
  3. Poultry: Chicken and turkey contain around 25-30mcg of selenium per 3 ounces of the meat
  4. Eggs: Per serving, one hard-boiled egg provides around 17 mcg of selenium

Plant Sources of Selenium

  1. Brazil nuts: They are one of the best sources of selenium. A handful of nuts (around 6-8) provide 544 mcg of selenium!
  2. Brown rice: You can meet 27% of your RDA (19 mcg) with one cup of boiled brown rice
  3. Sunflower seeds: They are power-packed and can be a great snack, containing around 20 mcg of selenium
  4. Mushrooms: In addition to being rich in vitamin D and iron, mushrooms are a great source of selenium, providing around 12 mcg per 100 grams

Summary

Selenium is an important mineral required for many processes like the regulation of the thyroid gland and anti-inflammatory activities. The body cannot produce selenium, and hence it needs to be consumed through dietary sources. For selenium to perform its function, it needs to be absorbed and utilized well by the body. Some genetic factors can put you at risk for selenium deficiency, which can lead to a weakened immune system, muscle pain, and hair loss. Health conditions like HIV and Crohn’s disease can also put you at risk for selenium deficiency. Ensuring adequate intake of selenium is important for the body. Some common food sources include rice, beans, wheat bread, and tuna.

References:

  1. https://en.wikipedia.org/wiki/Selenoprotein_P
  2. https://en.wikipedia.org/wiki/Glutathione_peroxidase
  3. https://medlineplus.gov/genetics/gene/cbs/
  4. https://academic.oup.com/jn/article/134/7/1736/4688592
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4321444/
  6. https://www.news-medical.net/health/Selenium-Toxicity.aspx
  7. https://pubmed.ncbi.nlm.nih.gov/9863072/
  8. https://pubmed.ncbi.nlm.nih.gov/17242315/
  9. https://www.sciencedirect.com/science/article/pii/S030698772031104X
  10. https://academic.oup.com/jn/article/137/3/690/4664703
  11. https://en.wikipedia.org/wiki/T_cell
  12. https://www.ncbi.nlm.nih.gov/pubmed/1873372
  13. https://www.ncbi.nlm.nih.gov/pubmed/18463429
  14. https://pubmed.ncbi.nlm.nih.gov/26516080/
  15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4899820/

Overview

Vitamin A plays a very important role in the overall development and maintenance of the body. This fat-soluble vitamin is stored in the liver and is available externally in two forms

Vitamin A is known to support a variety of metabolic functions. It helps with better vision and improves your immunity. Getting the right dose of vitamin A also plays a role in keeping the skin and teeth healthy. The right amounts of vitamin A protect the skeletal system and the soft tissues in the body.

In pregnant women, right vitamin A levels help with tissue repair after delivery and also keeps the risks of infections low.

Evolutionary Aspects: Have Humans Always Needed Vitamin A?

It took almost 130 years for researchers to identify the existence of vitamin A and understand its effects on the human body.

Early accounts of Vitamin A Deficiency (VAD) have only been recorded in terms of night blindness amongst children, soldiers, and sailors. Back then, the only solution offered was to consume cod liver oil or eat an excess of cooked liver. Doctors knew this worked, but didn’t understand why it worked. 

There were innumerable studies that tried to understand the effects of nutritional deprivation on animals and human beings between the mid-1800s and 1900s. 

In 1912, Sir Frederick Gowland Hopkins concluded in his clinical trial that an additional factor in milk apart from carbohydrates, fats, and proteins helped rats survive on only a dairy-based food plan. He won the Nobel Prize for this study later. 

This additional factor was narrowed-down to be a fat-soluble nutrient in 1918 and was finally identified as vitamin A in 1920.

In 1931, the International Conference on Vitamin Standards was first held in London and the league set to make standards and recommended values for all identified vitamins, including vitamin A.

Though people all over the world have become conscious about their nutritional intake, WHO states that about 250 million preschool children are still diagnosed with VAD. Making the right change in food habits, identifying the effects of one’s genes in his/her vitamin A requirements and taking vitamin A supplements, if needed, will all help bring down the risk of VAD.

Molecular Aspects- Getting Technical

We humans cannot produce vitamin A in our body, hence it is called an essential vitamin. We need to obtain it through diet or supplements. Vitamin A can be derived from both plant and animal sources.

Animal sources provide vitamin A in its active form, retinol, while plant sources provide vitamin A as carotene, an inactive form, which in-turn needs to be converted into the active form,  retinol. 

The genetics of some individuals predispose them to less efficient conversion of biologically inactive carotene to active retinol. They are usually advised to consume animal sources of vitamin A or take vitamin A supplements or consume higher amounts of plant sources to compensate for lowered conversion efficiency.

We will look into more details of specific genes that influence this predisposition in the following sections.

Did You Know?

Everyone knows carrots are a good source of vitamin A and that they can improve general eyesight.

Did you know where this idea stemmed from?

During World War II, the British government ordered citywide blackouts to prevent German bomber flights from identifying their targets. On the other side, the British defenses were safeguarding a secret Intercept Radar System that helped their British flyers see better despite blackouts. To keep this information a secret, the British Ministry let out official information stating their flyers were able to see better in the dark because of excess consumption of carrots! 

This detail has taken deep roots and is believed to date.  

Recommended Daily Intake Of Vitamin A

According to the U.S Department of Health & Human Services, here are the recommended values of vitamin A at every stage in life.

What Happens When You Take Excess of Vitamin A?

When you consume more vitamin A than recommended every day, here are some of the possible side effects recorded.

What Happens When You Have Vitamin A Deficiency?

When your Daily Value Intake of vitamin A is consistently lesser than the suggested levels, you could be at a higher risk of developing the below conditions.

What Are The Non-Genetic Factors Affecting Vitamin A Levels

Insufficient dietary intake

A key source of vitamin A to the body is the food we consume. Naturally, not including enough of vitamin A rich foods is a top non-genetic reason for Vitamin A Deficiency (VAD). Not taking enough vitamin A can be a result of an unhealthy lifestyle, lack of awareness on the importance of nutrients, or poverty/unavailability of food. 

People who suffer from chronic diarrhea and respiratory infections are also prone to having lower levels of vitamin A in the body.

Avoiding animal sources of vitamin A

Though vitamin A is available in both plant and animal sources, vegans have to depend exclusively on fruits and vegetables for their vit A needs. When vegans don’t plan their diet well and don’t consciously include enough carotenoid-rich foods, they can be prone to VAD.Veganism is hence a growing cause of concern as a non-genetic influence for VAD. If you follow a vegan lifestyle, you should be working on carefully choosing your food sources to prevent nutritional deficiencies.

Infants whose mothers show signs of VAD end up not getting enough Vitamin A in breast milk and hence are at a higher risk of developing VAD related health complications. 

What Are The Genetic Factors Affecting Vitamin A Levels

Mutations in both the TTR gene and the RBP4 gene can cause low levels of retinol in the body. The TTR gene produces a protein called transthyretin that transports vitamin A internally. The RBP4 gene (Retinol Binding Protein 4) produces the RBP4 transporting protein that delivers vitamin A from the liver to the tissues around. 

RBP works with transthyretin in the plasma and prevents the kidneys from filtering out excess vitamin A.

Two gene variations can cause VAD.

BCMO1 gene – The BCMO1 gene helps encode enzymes that convert the carotenes from plant-based food sources into forms that can be used by the human body.

CYP26B1 gene – This gene is responsible for bringing down the active form of vitamin A called retinoic acid. The SNP rs2241057 with G variant in this gene can cause an increased breakdown of retinoic acid and hence can result in lowered vitamin A levels in the body.

Recommendations For Healthy Vitamin A Levels

Here is what you should do to maintain the right levels of vitamin A in the body.

  1. Dietary diversification is vital: Include a variety of food sources in regular diet to match nutritional needs.
  2. Get your genetic testing done to know if you are likely to require more vitamin A rich foods than others.
  3. If you are diagnosed with VAD or your genetic data shows your requirement of vitamin A is higher than usual, consider supplements. The right dose of supplements helps keep your levels healthy.
  4. Choose Vitamin A fortified foods: Fortification is the process of enriching foods with specific vitamins and minerals. Choosing Vitamin A fortified foods can gradually bring your vitamin A levels to normalcy.
  5. The process of cooking and storage could cause vitamin A loss in foods. Try eating raw vegetables and fruits or use gentler cooking techniques like baking, steaming, or broiling to retain vitamin A values.

Summary

  1. Vitamin A is one of the most important fat-soluble vitamins needed for the healthy functioning of the body.
  2. Overconsumption and lack of essential vitamin A both can cause health conditions and unwanted side-effects.
  3. Genetically, some people are likely to require more vitamin A rich foods than others. They may need to compensate by taking supplements and fortified foods.
  4. you can get your normal dose of vitamin A easily from dairy products, meat sources, and fruits and vegetables. 
  5. Eating healthy, varied food choices and using gentler cooking methods will ensure your daily recommended vitamin A needs are met.

Reference

https://www.unicef.org/publications/files/Vitamin_A_Supplementation.pdf

http://ocw.jhsph.edu/courses/InternationalNutrition/PDFs/Lecture3.pdf

https://www.who.int/publications/cra/chapters/volume1/0211-0256.pdf

https://ods.od.nih.gov/factsheets/VitaminA-Consumer/

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

Dietary Antioxidants Hold the Key for Optimal Health

Well, you’ve heard it umpteen times that you are what you eat. You are probably gearing up already to redesign your food chart to throw in a few healthy choices based on nutritionists' recommendations.

In that case, you must be familiar with the term “antioxidants” – the magical word in the lexicon of health and nutrition that has become a synonym of power-houses of nutrients.

After all, who wouldn’t want to look perennially young, be energetic, and free of ailments! Though such a proposition may sound a fantastic probability, you can turn it into a possibility by opting for a sensible diet plan that includes foods rich in antioxidants.

Analyze your genetic variants for antioxidant needs

Antioxidants are naturally occurring chemicals in foods that help to counter the detrimental effects of oxygen free radicals, which form during normal metabolism.

External factors like pollution, ultra-violet radiation, and X-rays also produce free radicals that affect our system. Free radicals are deprived of oxygen and are responsible for the development of serious ailments, including cancer and heart disease.

Antioxidants convert the free radicals into harmless waste products that are eliminated from the body before any damage is done to the body. Thus, antioxidants act as scavengers that rid our body of free radicals that cause serious metabolic disorders by damaging the tissues and cells.

Daily consumption of antioxidants

Plants are one of the primary sources of antioxidants.

Fruits, vegetables, nuts, legumes, cereals, and seeds are foods that are naturally rich in antioxidants.

The best way to ensure adequate intake of the antioxidants is to consume a variety of fruits and vegetables through a diet consisting of 5 to 8 servings of fruits and vegetables per day.

Fruits and vegetables can help guard against heart disease, cancers, and the effects of radiation, pollution, and aging.

Antioxidant-rich foods

Fruits

Pomegranate, grape, orange, pineapple, plum, apple, and guava are some of the fruits that have the highest concentration of antioxidants.

In addition to being deliciously sweet, berries such as raspberries, blueberries, and strawberries are rich in antioxidants.

These berries are rich in proanthocyanidins - the antioxidants that can help prevent cancer and heart disease as well.

Vegetables

Broccoli, cabbage, carrots, spinach, lemon, ginger, peppers, parsley, kale, red beets, and tomato are vegetables rich in antioxidants.

Broccoli, a cruciferous vegetable, is one of the best antioxidants. It contains more vitamin C than an orange and has more calcium than a glass of milk.

In addition to minerals and vitamins, broccoli is filled with disease-fighting chemicals called phytonutrients.

Sulforaphane, a phytonutrient found in broccoli, has been shown to lower the risk of many types of cancers.

Tomato is the richest source of a powerful anticancer agent called lycopene.

Legumes

Broad beans, pinto beans, soybeans are some of the best antioxidant foods.

Cereals

Barley, millet, oats, corn are cereals rich in antioxidants.

Nuts and Seeds

Pecans, walnuts, hazelnuts, groundnut or peanut and, sunflower seeds contain a good amount of antioxidants.

Spices

Garlic, ginger, cloves, cinnamon, and oregano are antioxidant spices.

It also has been used as a natural antibiotic to kill off some strains of harmful bacteria.

Garlic is also useful for decreasing blood pressure and cholesterol, removing heavy metals from the body, preventing cancer, and acting as an antifungal and antiviral agent.

One clove of garlic contains vitamins A, B, and C, selenium, iodine, potassium, iron, calcium, zinc, and magnesium.

Green Tea

Green tea contains high concentrations of catechin polyphenols. It is also a powerful antioxidant and is very effective against cancer, heart disease, and high cholesterol.

Vitamins rich in antioxidants

Vitamin A

Vitamin A includes carotenoids and retinol.

They are essential for healthy eyes and prevent macular degeneration or age-related blindness.

The antioxidant in vitamin A neutralizes free radicals and boosts your immunity.

Beta-carotene, which is sometimes called provitamin A, can be found in fruits and vegetables such as tomatoes, broccoli, guavas, carrots, pumpkins, apricots, and all green leafy vegetables.

Vitamin B

All B vitamins are essential to a woman’s health.

They are essential for brain functioning, red blood cell formation, and DNA building. The important B vitamins are:

Vitamin C

Vitamin C, also called ascorbic acid, serves as an antioxidant that facilitates wound healing.

It helps in the formation of collagen, which is essential for the wounds to heal.

It also helps in the production of new red blood cells, which deliver oxygen to your brain and to the other cells of your body.

Vitamin C is present in citrus fruits, grapefruits, strawberries, tomatoes, kiwi, oranges, and broccoli.

Vitamin D

Also called cholecalciferol, this vitamin functions as a hormone and regulates bone homeostasis, together with calcium.

It is an important vitamin for women as it maintains strong and healthy bones.

A deficiency of this vitamin can cause you to have osteoporosis.

Exposure to sunlight helps your body produce vitamin D.

The dietary sources of vitamin D are eggs, fish, and vitamin-fortified products like milk.

Vitamin E

Vitamin E or tocopherol acts as an antioxidant that aids in the production of red blood cells and the maintenance of the integrity of cellular membranes.

It also helps to slow age-related changes in the body.

Sources of this vitamin include nuts and nut products, wheat germ, cod liver oil, corn oil, and safflower oil.

Eat healthy to stay healthy

In reality, eating healthy is never a cumbersome task. It all starts with a simple step of ringing in variety to your table.

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Updated 22 May, 2020

PON1 gene and Antioxidant Needs

An introduction 

PON1 gene in humans is located on the long arm of chromosome 7.

This gene was the first discovered gene of the paraoxonase multigene family along with the PON2 and PON3 genes.

The PON1 gene codes for the enzyme serum paraoxonase/arylesterase 1 or PON1 that has esterase and paraoxonase activity.

The PON1 enzyme is composed of 354 amino acids and is synthesized by the liver.

PON1 associates itself with High-Density Lipoprotein (HDL) in the circulation.

The PON1 gene shows many polymorphisms in the coding and promoting regions.

Polymorphisms in the PON1 gene have an association with coronary artery disease and diabetic retinopathy. 

PON1 association with antioxidant needs

PON1 plays a major role in oxidative stress and inflammatory response by virtue of its association with HDL cholesterol in the body.

HDL facilitates the secretion of the PON1 enzyme, which in turn prevents the oxidation of HDL and stimulates cholesterol efflux from the cells.

These together offer an atheroprotective function to HDL.

What are antioxidants? 

As the name goes, these substances and compounds inhibit oxidation in the body. 

Antioxidants are natural compounds that help neutralize free radicals in our bodies.

Free radicals are substances whose elevated levels can be harmful to the body. 

The elevated levels have an association with diseases like cancer, heart disease, diabetes, and aging.

What is the function of antioxidants? 

Our body cells constantly produce free radicals as a reaction to internal body and environmental pressures and stresses.

The cells in our body are responsible for the production of these free radicals. 

These are unstable molecules, and thus can cause slow cell damage.

Since these free radicals are reactive oxygen species, the antioxidants naturally counter them.

Antioxidants are neutralizers of these free radicals and can be obtained by consuming foods that are rich in them.

In individuals who are healthy and disease-free, there is a balance of antioxidants that counter the effects of the reactive free radicals.

What’s the genetic link?

[table id=129 /]

SNP rs854560 is a polymorphism that is present on the PON1 gene associated with antioxidant needs.

The variants of this SNP affect levels of the PON1 enzyme and have an association with coronary diseases and diabetes. The T allele is the more favorable form of the SNP and codes for methionine, which leads too elevated levels of paraoxonase.

This is beneficial to the body.

However, the A allele codes for leucine; this leads to reduced paraoxonase activity, which is harmful to the body.

[table id=130 /]

SNP rs662, also called as Q192R is a polymorphism of the PON1 gene.

The C allele codes for arginine, whereas the less common T allele codes for glutamine.

The presence of the TT allele can imply lower or decreased levels of PON1 enzyme activity. Higher the PON1 enzyme activity, the lower is the risk for heart disease.

The TT allele also increases the risk of coronary heart disease by 2.3x and also increased the risk of vascular dementia, kidney disease, ischaemic heart disease, and male infertility.

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References

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5327813/
  2. https://www.snpedia.com/index.php/Rs662

Updated on June 09, 2020

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