Field Notes

Unhealthful Neighborhood Food Environments Linked to Poor Birth Weight

Higher neighborhood density of unhealthful retail food establishments was associated with a higher risk of delivering a baby that was large-for-gestational age, according to a new study at Columbia Mailman School of Public Health, while neighborhoods with a high density of healthful food retail establishments were linked with a lower risk of giving birth to a baby that was small-for-gestational age. Babies born either small- or large-for-gestational age, a measure of birth weight adjusted for length of pregnancy, are at greater risk of long-term health complications, but until now, little was known about how neighborhood characteristics, including walkability and the food environment, may affect birthweight outcomes. The results are published in JAMA Network Open.

To evaluate links between birth weight and retail food environments and walkability in neighborhoods of New York City, the researchers analyzed the records of 106,194 singleton births in the 2015 Vital Statistics records from the New York City Department of Health and Mental Hygiene. Full-service supermarkets and fruit and vegetable markets were classified as healthful, and fast-food outlets, convenience stores, and candy stores as unhealthful.

“Our prior work has shown that these healthful and unhealthful neighborhood retail food environment classifications are associated with residents’ BMI in New York City,” says Eliza Kinsey, PhD, the first author and a former postdoctoral fellow in epidemiology at Columbia Mailman School, now an assistant professor at the University of Pennsylvania.

The prevalence of babies born small-for-gestational age was 13% and the percent born large-for-gestational age was 8.4%. Residing in the densest healthful retail food environment compared with the lowest was associated with an 11% lower risk of delivering a baby whose weight was low-for-gestational age. Conversely, compared with residing in a neighborhood with the lowest density of unhealthful retail food outlets, residing in a neighborhood with the highest density of these unhealthful food outlets was associated with a 16% to 18% increase in the risk of a baby being born large-for-gestational age. There were no significant associations between neighborhood walkability and birthweight outcomes.

“Our results further support the value of encouraging use of urban design and planning guidelines to improve food environments and ultimately healthy pregnancies and birth weight,” says senior author Andrew Rundle, DrPH, a professor of epidemiology at Columbia School of Public Health.

The high density and low car ownership may limit the generalizability of the findings to populations outside of New York City, particularly suburban and rural areas, the researchers note. “However, given that the percentage of the world population living in urban areas is projected to grow to 68% by 2050, our findings for New York City are likely relevant for much of the global population,” Rundle says.

— Source: Columbia University’s Mailman School of Public Health

 

Omega-3 Fatty Acids Linked to Slower Decline in ALS

People with amyotrophic lateral sclerosis (ALS) who eat more foods high in certain omega-3 fatty acids like flaxseed oil, walnuts, canola oil, and pumpkin seeds may have a slower physical decline from the disease and a slightly extended survival. The study, which looked at the survival of people with ALS over the course of 18 months, was published online in Neurology, the medical journal of the American Academy of Neurology. Researchers also found that an omega-6 fatty acid may be beneficial. The study doesn’t prove that these omega fatty acids slow decline of ALS or extend survival; it only shows an association.

ALS is a rare, progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. People with ALS lose the ability to initiate and control muscle movement, which often leads to total paralysis and death. The average life span after diagnosis is two to five years.

“The link our study found between diet and ALS is intriguing and suggests, but does not prove, that people with ALS may benefit from incorporating more omega-3 fatty acids into their diet,” says Kjetil Bjornevik, MD, PhD, of Harvard University in Boston, and a member of the American Academy of Neurology. “It will now be important to conduct additional research looking specifically at the plant-based omega-3 fatty acid alpha-linolenic acid in people with ALS to further explore this possibility.”

The study involved 449 people who had ALS with an average age of 58, who were followed over 18 months. Of the total participants, 126, or 28%, died by the end of the study.

Researchers looked at levels of omega-3 fatty acids in participants’ blood. They divided them into four groups based on lowest to highest amounts.

Participants took a test to assess their disease progression and severity of symptoms. The test measured 12 aspects of physical function, including swallowing, speaking, chewing, and the ability to use muscles in the hands, arms, legs, and torso, as well as respiratory function. Each category was scored from zero, meaning no ability, to four, meaning normal ability. Total scores ranged between zero to 48, with higher scores indicating better function and less severe symptoms.

Researchers found that an omega-3 fatty acid called alpha-linolenic acid was the most beneficial. This acid is found in many seeds and oils, including flaxseed, walnuts, chia, hemp, and several common vegetable oils.

The people with the highest amount of alpha-linolenic acid had an average score of 38.3 at the start of the study, while the people with the lowest amount had an average score of 37.6.

A lower number of people from the group with the most alpha-linolenic acid died during the study, with 21 deaths, or 19%, compared with people in the lowest group, with 37 deaths, or 33%.

After adjusting for age, sex, and ethnicity, people with the highest amounts of alpha-linolenic acid had a 50% lower risk of death during the study compared with people with the lowest amount.

Higher levels of a specific omega-3 fatty acid called eicosapentaenoic acid that’s found in fatty fish and fish oil supplements also were associated with a lower risk of death during the study.

In addition, researchers discovered that an omega-6 fatty acid called linoleic acid found in vegetable oils, nuts, meats, seeds, and eggs was associated with a lower risk of death during the study.

A limitation of the study is the lack of access to data on the overall diet of the participants, including other nutrients and supplements as well as total caloric intake, which could all be associated with survival time in ALS.

— Source: American Academy of Neurology