By Stacy Kennedy, MPH, RD, CSO, LDN; Reboot Nutritionist
Diet, exercise and genetics are all factors that we know contribute to maintaining a healthy weight and promoting or discouraging disease risk. Beyond these general influencers, there are various specifics that come into play based on ethnicity. In other words, beyond just genetics, how does one’s ethnicity and culture impact body weight and overall health? And how can we tease out socioeconomic status (SES) or income and poverty from the broader conversation of culture and ethnicity?
A study in the American Psychological Association showed that being poor means greater lifelong health risks, regardless of ethnicity. Low SES and poverty are dramatically linked to risk of disease, like heart disease and contributing risk factors for cancers and other chronic illness through sedentary lifestyle, heavy drinking and cigarette smoking as well as cumulative exposure to stress. This interconnected, complex issue is important to keep in mind when considering ethnicity’s link to BMI and associated health risks.
Let’s look more closely at BMI. Body Mass Index (BMI) was accepted as a gold standard for evaluating weight and risk of illness back in the 1990’s. As a college student in 1994, I presented a poster project on this “novel” topic at the National Institutes of Health! You can calculate your BMI here. In addition to BMI, waist-hip ratio also remains an important predictive marker for chronic illness and is more routinely used abroad.
There is no perfect measure or one-size-fits-all when it comes to assessing health risks. Researchers have known for years that different cultures have distinct risk factors even within the normal range for BMI. One reason is that BMI does not completely factor in body composition, like muscle to fat ratio or where excess body fat is located. Storing excess body fat in the abdomen or central region carries higher risk for disease. Because of issues like these, BMI can overestimate risk in those with significantly high muscle mass, like some professional athletes, and underestimate risk in other cases.
For example, Asians with the same BMI as whites, have more than double the risk for developing diabetes. In fact, Harvard School of Public Health reports that, “for every 11 pounds (5 kg) Asians gained in adulthood, they had an 84% increase in their risk of type 2 diabetes compared to whites at the same weight.” Asians who gain excess weight in adulthood also have a higher risk, at the same BMI as whites, for developing as well as dying from heart disease and high blood pressure.
Both blacks and Latinos also have a disproportionately elevated risk for diabetes, but less so compared to the Asian populations studied. One theory is that when Asians pack on excess weight, it tends to be centralized adiposity, better known as that evil “belly fat.”
More than 40% of African American adults have been diagnosed with high blood pressure (HBP). HBP is shown to occur earlier in life and be more severe in blacks vs whites in the US. There are many theories as to why African Americans are at higher risk than whites, including increased rates of obesity and diabetes. However, the negative effect of dietary sodium is another culprit. Not all persons with HBP are “salt sensitive” meaning that not everyone’s blood pressure goes up from consuming more sodium. This is not the case for African Americans, where it’s believed this group has a gene that causes them to be more salt sensitive. Just an extra half teaspoon of salt a day can raise BP and stroke risk significantly in this population. What are the greatest contributors of excess dietary sodium? No surprises here: packed, frozen and processed foods.
Not long ago, African American women were at disproportionate risk for breast cancer. Today, rates match those for white women, however African American women have a 42% greater risk of dying from breast cancer than white women. Despite better access to mammograms and early screening, African American women continue to be to be diagnosed more frequently with advanced breast cancers, perhaps linked to reproductive factors like age of menarche and lifelong exposure to estrogen, or other biological factors. African American girls are at higher risk of childhood obesity compared to whites. Girls who are heavier get their periods sooner, showing how a higher BMI in childhood is linked with greater likelihood of disease risks later in life.
For Hispanics, the largest racial/ethnic minority in the US, overall death rates are actually 24% lower than for whites. However for liver disease and diabetes, this group has a 50% greater risk. Smoking, insurance coverage and being born in the US vs. another country varies within subgroups and can have impacts on health risks. For example, smoking rates overall among Hispanics are significantly lower than whites (14% vs 24%), but within subgroups of Puerto Rican and Cuban males, it is actually greater (24% and 26% respectively).
The past 10-15 years we’ve seen much debate about redefining BMI to have different cut-offs based on ethnicity. In the US the BMI ranges remain the same regardless of ethnic group:
<18.5 = Underweight
18.5-24.9 = Healthy Weight
25-29.9 = Overweight
30+ = Obese
But overseas, new cutoffs are being established to impart better preventive strategies to keep populations healthy. For example, you’ll find tighter accepted ranges in China and Japan, where healthy weight has a BMI cutoff of 24 and obesity begins at 28. In India, it’s even more restrictive with healthy weight upper limit at 23 and obesity starting with BMI of 27.
New studies in the US looking at the health of our children show some bleak facts that raise the red flag. Disproportionately as compared to white children, children from African American and Latino households have significant risks. One third of children from these ethnic groups meet criteria for overweight or obese!
Factors that help reduce risk in kids include:
While ethnicity may play a role, SES, access to healthy options and ability for parents to be involved when working long hours are all intertwined in this picture of elevated risk. That’s why programs that help kids and families have affordable access to healthy options, like school gardens and local fresh foods, while limiting marketing and excess exposure to soda, candy, and other common sources of added sugars, like chocolate milk served in schools, and sodium-laden processed foods, are just as important or more so in my opinion, than throwing additional education into the mix.
Kids and parents know all too well that veggies are healthier than cookies. It’s not lack of desire, motivation, knowledge or being a “picky eater,” but access and systems that are the primary link to poor nutritional health in our youth. Setting up better systems for families, that support access to healthy habits, is what’s needed to help level the playing field on ethnicity, weight and health risks.