PON1 Gene: All You Need To Know About Your Antioxidant Needs

PON1 gene: 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 are associated with coronary artery disease and diabetic retinopathy. 

 

PON1 association with antioxidant needs

PON1 is considered to play 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 body.

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

The elevated levels are known to be associated with diseases like cancer, heart disease, diabetes, and even 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.

These free radicals are basically waste substances which are produced by the cells in the body by way of body processes or reaction to the environment.

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

Since these free radicals are reactive oxygen species, they are naturally countered by antioxidants produced by the body itself.

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.

 

How do antioxidants work? 

Antioxidants are constantly at play within our body to protect it from harmful free radicals.

Food components that function as antioxidants include vitamin A, C, and E, carotenoids like lycopene, beta-carotenoids, lutein, zeaxanthin, and minerals such as selenium.

Antioxidants undergo single electron reactions with the free radicals to neutralize them.

They are essentially of two types: Enzymatic and non-enzymatic.

The body naturally protects itself from the reactive oxygen species or free radicals by using enzymatic antioxidants.

These antioxidants reduce the levels of lipid hydroperoxide and hydrogen peroxide and prevent lipid peroxidation, thereby protecting the integrity of the cell membranes.

Non-enzymatic antioxidants are of two types: Natural and synthetic

Natural antioxidants include vitamins, bioflavonoids, carotenoids, etc.

 

What’s the genetic link?

SNPAlleleRisk
rs854560TBeneficial of antioxidant needs
rs662CRisk of antioxidant needs

 

SNP rs854560 is a polymorphism that is found on the PON1 gene.

The variants of this SNP affect levels of the PON1 enzyme and have been associated 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 that leads to reduced paraoxonase activity, which is harmful to the body.

SNPAlleleRisk
rs854560AA2x Higher risk of Coronary Heart Disease and Diabetic retinopathy
rs854560AT2x Higher risk of Coronary Heart Disease and Diabetic retinopathy
rs854560TT1.8x Higher risk of Coronary Heart Disease and Diabetic retinopathy.

 

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.

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

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

 

Antioxidant superfoods

Foods that are rich in antioxidants, vitamins, and minerals are now known as superfoods because they have the potential to not just minimize but also prevent cell damage due to the free radicals.

Some antioxidant-rich superfoods are:

Blueberries

These are one of the richest sources of antioxidants available.

This is due to the pigments like anthocyanins that they contain, along with vitamins and minerals that help reduce inflammation in the body and also strengthen the immune system.

 

Grapes

The purple, red and blue varieties of grapes, are rich in antioxidants, mainly anthocyanin, and proanthocyanidin that are phytochemicals.

These compounds protect the body cells from free radical damage and the presence of vitamin C and selenium further accentuates this effect.

 

Dark Chocolate

Though eating regular sweetened chocolate can cause health problems like diabetes, consuming dark chocolate has many health benefits.

This is due to the cocoa content.

The higher the cocoa content, the higher is the antioxidant content in the dark chocolate.

The antioxidants present in cocoa reduce bad cholesterol levels, increase good cholesterol or HDL, and reduce inflammation in the body. All these prevent the development of cardiac conditions.

 

Red berries

Red berries such as strawberries and raspberries are also rich in antioxidants like blueberries.

However, they contain another phytochemical called ellagic acid that protects the body cells from the harmful free radicals.

 

Nuts

Nuts contain a wonderous compound called omega-3 along with vitamins, fiber, proteins, and minerals.

They also contain good amounts of phytochemicals such as resveratrol and other plant sterols that help in reducing blood cholesterol levels.

In totality, nuts are extremely healthy and have antioxidants to protect your body from oxidative stresses.

 

Dark green vegetables

While dark green vegetables are rich in fiber and minerals like magnesium and calcium, they are also rich in phytochemicals such as kaempferol that is a strong antioxidant and can help the body fight cancer-causing free radicals.

Other leafy greens like leeks have lutein and quercetin, both of which are antioxidants too. Some of these leafy greens include spinach, kale, 

Other antioxidant-rich superfoods include:

  • Red Cabbage
  • Goji Berries
  • Tea
  • Beans
  • Beetroot
  • Whole grains
  • Fish
  • Artichokes

 

Which vitamin is the best antioxidant? 

The richest food nutrients that function as antioxidants include vitamins, carotenoids and minerals like selenium.

Among the vitamins, vitamin C and E are the major antioxidants. 

Vitamin C can be found in:

  • Citrus fruits
  • Berries
  • Broccoli
  • Cauliflower
  • Grape Fruit
  • Tomatoes
  • Sweet Potatoes
  • Strawberries
  • Peppers
  • Mangoes
  • Kale
  • Carrots
  • Avocado

 

Food sources of vitamin E:

  • Avocado
  • Boiled Broccoli
  • Chard
  • Mustard
  • Turnip greens
  • Papaya
  • Spinach
  • Nuts
  • Sunflower seeds

 

References

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

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