A person’s genes can make them more susceptible to developing type 2 diabetes. However, environmental factors such as diet and exercise can influence how those genes behave.
Type 2 diabetes has a stronger link to family history than type 1 diabetes. Other risk factors for the condition include age, inactivity, and having a high body weight.
Read on to learn more about the genetic link with type 2 diabetes, which genes it can involve, and how someone might be able to influence whether they develop the disease.
Genetics appears to play a role in type 2 diabetes. Scientists estimate it has
Heritability measures how much genes influence variations between people, so this figure may explain why some people get type 2 diabetes while others do not. It may also explain why diabetes appears more common in some families.
However, it is important to note that current research
Heritability estimates can vary depending on the population researchers study and the methods they use. Previous studies suggest that genetics may be less influential in some populations.
Additionally, while genes can increase the risk of type 2 diabetes, genes alone cannot cause the condition. According to the American Diabetes Association (ADA), studies in identical twins have shown that even if one twin gets type 2 diabetes, the other twin will only develop it around half the time.
Experts believe that environmental factors, such as eating patterns and lifestyle, trigger the onset of type 2 diabetes. These can also run in families as learned behaviors.
Type 2 diabetes is polygenetic, meaning many genes influence the risk of getting it.
Scientists have identified at least 150 genetic variations that play a role, but many of these variations are common in the general population. They do not guarantee a person will develop the condition.
According to an older 2013 review, some genes with significant links to type 2 diabetes include:
- CAPN10: This gene encodes enzymes that degrade proteins. It was the first gene that scientists confirmed had a definitive link with type 2 diabetes.
- TCF7L2: This protein-coding gene has the strongest links to type 2 diabetes across all racial groups.
- ABCC8: This gene may impair the release of insulin.
- GCGR: This gene is a glucagon receptor.
- GCK: This is a gene for the enzyme glucokinase, which speeds up glucose metabolism and acts as a glucose sensor.
- GLUT2: This gene encodes for a glucose transporter, which regulates the entry of glucose into pancreatic beta cells.
- SLC2A2: This gene regulates the entry of glucose in pancreatic beta cells and triggers insulin secretion.
- HNF4A: This regulates genes in the liver and pancreas.
- HNF4A: This is the insulin hormone gene.
- KCNJ11: This is the gene for the potassium channels that trigger the release of insulin.
- LPL: This is the enzyme lipoprotein lipase, which breaks down triglycerides (fats).
- PPARG: This gene regulates fat cell differentiation.
- PIK3R1: This gene has a role in insulin signaling.
A person’s genes interact with their environment to either switch their genes off or on. This is known as epigenetics.
Epigenetic changes do not alter the DNA itself, but instead affect gene expression. Environmental factors such as diet, exposure to cigarette smoke, and infections can result in epigenetic changes.
For example, a 2019 review states that past research has shown that certain genes linked to type 2 diabetes, such as TCF7L2, may interact with dietary carbohydrates in ways that influence diabetes risk.
However, this area of research is still developing, and more studies are necessary before these findings can guide dietary recommendations.
People do not inherit type 2 diabetes directly from their parents. Instead, they can inherit a greater vulnerability to the condition through a mixture of genes and environmental factors.
Their individual risk will depend on various factors, such as which genes they inherited, how many they inherited, and whether they are switched “on” or “off”.
Generally, though, the more first-degree relatives a person has, the higher the risk.
Things that may help to prevent type 2 diabetes include:
Nutrition
Eating a nutritious diet can help to reduce the risk of type 2 diabetes, as well as other conditions.
A 2019 review of past research notes that there is some observational evidence that getting enough of the following nutrients may support healthy blood sugar levels and reduce inflammation:
- vitamin D
- vitamin K
- vitamin E
- magnesium
- antioxidants, such as beta carotene
More research is necessary to confirm the effects. That said, getting adequate nutrients from a balanced diet is generally beneficial.
Fruits, vegetables, nuts, and seeds are good sources of many of these nutrients. For vitamin D, people can take supplements if they live in a colder climate, or try safe sun exposure.
It is also important to consider the balance of foods within a person’s eating pattern. Diets high in the following have an association with type 2 diabetes:
- saturated fats
- sugar-sweetened drinks
- processed meats, such as sausage or bacon
- red meat
- alcohol
Gradually switching from these foods to alternatives, such as lean proteins, unsweetened drinks, or healthy fats, may help.
Weight management
The above strategies can also help a person maintain a moderate weight, which
However, if a person finds that changing their eating pattern or lifestyle does not help, or they are gaining weight unintentionally, they should speak with a doctor if they can.
Doctors can provide additional help for weight management, including medications or support from dietitians.
Education and programs
People in the United States can join a National Diabetes Prevention Program to learn how to make changes to help reverse prediabetes and prevent type 2 diabetes.
Other factors
A 2019 review outlines factors that studies have associated with type 2 diabetes, including:
- alcohol intake
- smoking
- inactivity
- stress
- insomnia
- antibiotics
People may be able to reduce their risk of type 2 diabetes by avoiding or addressing these factors, if relevant. For example, they could stop smoking, seek support for stress or insomnia, and take steps to avoid infections.
If people wish, they can take a test to determine if they have specific genes that put them at higher risk for developing type 2 diabetes. However, the predictive value of these tests is limited, so doctors do not routinely offer them.
There are companies that provide them via mail-order kits, but it is important to remember that the results do not guarantee a person will or will not get type 2 diabetes. That said, genetic testing may motivate some people to change their diet and lifestyle to help reduce their risk.
People should consider whether genetic tests are worth the costs. Before purchasing, it may help to speak with a doctor or endocrinologist about the value of these tests.
Some genes can increase the risk of type 2 diabetes. However, genes cannot cause type 2 diabetes on their own. Environmental factors play a significant role.
As a result, people can reduce their risk of type 2 diabetes, even if they have inherited genes that increase the risk. This may involve changes to nutrition and physical activity, or stopping smoking.