Changes To Traditional Diets After Migration

Immigration is usually accompanied by environmental and lifestyle changes. Over time, immigrants tend to adopt the dietary habits and food culture of their new country, leading to changes in their own cultural practices and traditional diets.

What is good about traditional diets?

In the book “The Jungle Effect”, Dr Daphne Miller describes her travels to regions in the world where indigenous populations have very low levels of chronic diseases. Dr Miller explains that traditional diets are not just about the food itself, which is fresh, seasonal and locally grown, but they also emphasise the cultural aspects of eating, such as traditional style of cooking, smaller quantities of food, recipes passed down through generations, and the pleasure of communal eating.

For example, some of the world’s longest living people live in Okinawa, Japan, where there are also very low rates of breast and colon cancer. Their traditional diet focuses on vegetables, seafood, soy, clear broth, rice, green tea and seaweed. The Okinawans eat until they are 80 percent full. It means they eat until they are not hungry, rather than eat until they are full. This could be the difference between losing weight or gaining it.

Traditional Mediterranean diet

Another well-known diet is the traditional Mediterranean diet. It is associated with lower rates of heart disease and cancer, and increased longevity. The Mediterranean diet consists mainly of olive oil, whole grains, fresh fruit and vegetables, legumes, and a moderate amount of fish, dairy and meat.

In contrast, our current Western diet is high in processed and refined foods that are stripped of their nutrients, high in fat and sugar, and low in fruit and vegetables. Many people in Western society experience chronic stress, environmental pollution, insufficient physical activity, and insufficient sleep. 
It is no surprise then, that when immigrants move to a Western country and adopt a Western-type diet, they may experience a significant decline in health.

Health implications of migration

Most of the research has been focusing on the negative health effects on Asian immigrants to the United States and Europe. After migration, Asians tend to consume bigger portion size and foods that are higher in energy (calories), as well as more fatty foods, more meat, and less fibre, as a result of replacing whole grains with refined grains and sugary drinks. The risk of chronic disease is higher in migrant populations, particularly South Asians, African Caribbeans, and Mexicans.

• Obesity. Studies found that South Asians (from India, Pakistan, and Sri Lanka) migrants in Europe had higher Body Mass Index (BMI) and waist circumference than their counterparts with similar cultural and genetic background in the country of origin. Similarly, Korean and Chinese were at an increased risk for overweight and obesity the longer they resided in the United States. It is estimated that it can take 10-14 years for this effect to manifest.
• Diabetes. British South Asians have nearly fivefold higher rates of diabetes than the general population in Britain.
• Breast cancer. Exposure to Western lifestyles has been shown to increase breast cancer risk in female Asian migrants to the United States. Studies show higher breast cancer incidence rates among Asian women living in the United States than among those living in Asian countries.

How long does it take for the diet to change?

Most migrants experience changes in their diet to some degree, but the length of time and degree of change vary. Factors influencing change include such things as country of origin, socio-economic status, education level, availability and cost of traditional foods. 

Gender and age at the time of migration, as well as stress level, language barrier and social isolation may also play a role. Migrants who settle in neighbourhoods populated with other immigrants from similar ethnicity seem to maintain more of their traditional food culture and experience less ill health. The children of migrants usually adopt the new eating habits of their peers at school, before their parents.

Nutrition Transition

It has been suggested that the change, also called Nutrition Transition, takes place in stages. 

Migrants adapt more easily and rapidly to fatty foods and sugary snacks and drinks, especially the younger generation.
Second, there is a reduced intake of legumes (beans and lentils) and an increased intake of meat, fish and dairy.
The last food group to be replaced are staple foods: the carbohydrate grains, such as rice and wheat. For example, pizzas, French fries, cakes and breakfast cereals may replace rice, which is a staple food in many Asian countries. The chapatti or roti, traditionally made from whole-wheat flour, may be prepared with white flour.

Should I eat a diet that matches my ancestry?

The study of how genes and nutrients interact to affect our health is called nutrigenomics.

It is becoming increasingly clear that not all people respond equally to diet. More and more people are choosing to undergo comprehensive genetic testing so they can understand how to eat according to their genes. However, tests are costly, and research is still ongoing.
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Dr Miller prefers you eat to your taste buds rather than your genes, as long as you eat anything but the standard American (Western) diet. Rather than following an Americanised/Westernised version of the traditional diets, follow the principles of different traditional diets: look for traditional recipes, traditional style of cooking, and quality of the ingredients. Cut down on the amount of food you consume, and adopt a healthy lifestyle. For example, you do not need to eat a Japanese diet if it is not to your taste, but adopt the Okinawan principle of eating until 80 percent full. Use olive oil on your salads and for cooking like the people in the Mediterranean.

References

Holmboe-Ottesen, G. & Wandel, M., 2012. Changes in dietary habits after migration and consequences for health: a focus on South Asians in Europe. Food & nutrition research, 56. Available at: http://www.ncbi.nlm.nih.gov/pubmed/23139649

Lesser, I.A., Gasevic, D. & Lear, S.A., 2014. The association between acculturation and dietary patterns of South Asian immigrants. PloS one, 9(2), p.e88495. Available at: http://www.ncbi.nlm.nih.gov/pubmed/24558396

Miller, D 2009, The Jungle Effect: A Doctor Discovers the Healthiest Diets from Around the World--Why They Work and How to Bring Them Home, HarperCollins Publishers Inc, New York.

Ro, A., 2014. The longer you stay, the worse your health? A critical review of the negative acculturation theory among Asian immigrants. International journal of environmental research and public health, 11(8), pp.8038–57. Available at: http://www.ncbi.nlm.nih.gov/pubmed/25111874

Ruiz-Núñez, B. et al., 2013. Lifestyle and nutritional imbalances associated with Western diseases: causes and consequences of chronic systemic low-grade inflammation in an evolutionary context. The Journal of Nutritional Biochemistry, 24(7), pp.1183–1201. Available at: http://www.ncbi.nlm.nih.gov/pubmed/23657158

Talegawkar, S.A. et al., 2016. Dietary intakes among South Asian adults differ by length of residence in the USA. Public health nutrition, 19(2), pp.348–55. Available at: http://www.ncbi.nlm.nih.gov/pubmed/25990446

Ziegler, R.G. et al., 1993. Migration patterns and breast cancer risk in Asian-American women. Journal of the National Cancer Institute, 85(22), pp.1819–27. Available at: http://www.ncbi.nlm.nih.gov/pubmed/8230262