ABCG8

Protein:

ATP Binding Cassette SGM8

SNP ID:

T322+431C
G55C

ATP Binding Cassette SGM8 (ABCG8) is a transporter protein which controls the absorption and excretion of cholesterol and other lipids in the gut, and is encoded for by the ABCG8 gene ¹.

ABCG8 is expressed in the liver, colon and intestine and acts as a half-transporter protein, meaning it preferentially shuttles molecules in one direction. In the intestine it functions to limit the absorption of cholesterol and other fats from dietary intake. However, it then promotes the secretion of the majority of cholesterols and other fats which do manage to get absorbed into the bile which is then excreted from the body.

There are two SNPs in ABCG8 that are associated with differing poor health outcomes; rs6544713 or T322+431C is associated with an increased cardiovascular risk, whereas rs11887534 or G55C is associated with an increased risk of developing gallstones.

T322+431C

Science Grade :

B+

Heart Health

rsID Number	Major Allele	Minor Allele	Minor Allele Frequency (%)
rs6544713	c	t	17

Risk Description

The risk ‘T’ allele of T322+431C in the ABCG8 gene was one of several SNPs that were flagged as being associated with an increased risk of developing coronary heart disease ². The ‘T’ allele was associated with increased levels of LDL which are themselves known to be associated with an increased cardiovascular risk ³.

The authors of the study do not describe a mechanism as to how the ‘T’ allele of T322+431C contributes to an increased level of LDL detected in the blood. However, based on the known function of ABCG8 it is possible to hypothesise that the ‘T’ allele leads to a reduction in ABCG8 function promoting greater uptake of cholesterol and other lipids from the diet, and a reduced secretion of these lipids into the bile.

Indirect Nutrients:^*

Ingredient	Active Ingredient	Effect
Oleic acid		Oleic acid, sometimes called omega-9 fatty acid, is a major component of olive oil and is thought to be a major driver of the beneficial cardiovascular effects associated with the so called Mediterranean diet ⁴. Oleic acid supplementation, or the inclusion of olive oil in the diet, may benefit those carrying the the risk ‘T’ allele of T322+431C, which is associated with increased LDL cholesterol ⁵.
Tangerine Oil	Tangeretin	Tangeretin a flavone compound which is isolated from tangerine oil. Able to reduce both the levels of LDL cholesterol and total blood lipids ⁶. Supplementation may therefore benefit those carrying the the risk ‘T’ allele of T322+431C.

Ingredient

Active Ingredient

Effect

Oleic acid

Oleic acid, sometimes called omega-9 fatty acid, is a major component of olive oil and is thought to be a major driver of the beneficial cardiovascular effects associated with the so called Mediterranean diet ⁴.

Oleic acid supplementation, or the inclusion of olive oil in the diet, may benefit those carrying the the risk ‘T’ allele of T322+431C, which is associated with increased LDL cholesterol ⁵.

Tangerine Oil

Tangeretin

Tangeretin a flavone compound which is isolated from tangerine oil. Able to reduce both the levels of LDL cholesterol and total blood lipids ⁶.

Supplementation may therefore benefit those carrying the the risk ‘T’ allele of T322+431C.

Discuss this information with your doctor before taking any course of action.

Citations:

G55C

Science Grade :

Gastrointestinal Health

rsID Number	Major Allele	Minor Allele	Minor Allele Frequency (%)	Major Amino Acid	Minor Amino Acid
rs11887534	g	c	5	Asp	Asn

Risk Description

The ‘C’ allele of G55C in the ABCG8 gene is strongly associated with an increased risk of developing gallstones. Those carrying one copy of the ‘C’ allele were at twice the risk, whereas those carrying two copies of the ‘C’ allele were at seven times risk ⁶.

It is proposed that the risk ‘C’ allele of G55C is actually a gain of function SNP. Decreased levels of cholesterol and LDL cholesterol are observed in the blood of those carrying the risk ‘C’ allele ⁷; whereas the cholesterol content of their bile was increased ⁸. Together, these point towards an increased secretion of cholesterol into the bile, which then leads to the formation of gallstones ⁹.

Indirect Nutrients:^*

Ingredient	Active Ingredient	Effect
Iron		A lack of dietary iron has been associated with cholesterol gallstone formation ¹⁰. Therefore, iron supplementation may benefit those carrying the risk ‘C’ allele of G55C which is associated with an increased risk of cholesterol driven gallstone formation.
Vitamin C	Ascorbic Acid	Supplementation with vitamin C has been shown to protect against the formation of gallstones ¹¹. Therefore, carriers of the risk ‘C’ allele of G55C may benefit from increasing dietary vitamin C intake or vitamin C supplementation.

Discuss this information with your doctor before taking any course of action.

Risk Description

Indirect Nutrients:*

Citations:

Risk Description

Indirect Nutrients:*

Citations:

Indirect Nutrients:^*

Indirect Nutrients:^*