People who do shiftwork are more likely to have a diet that promotes chronic inflammation—which may partly explain the health risks associated with shiftwork, reports a new study in the Journal of Occupational and Environmental Medicine.
Chronic, low-grade inflammation – the ongoing release of inflammatory immune compounds – is now recognized as a major determinant of many age-related diseases including heart disease, stroke, Alzheimer’s, diabetes and metabolic syndrome.
Researchers from the University of South Carolina, Columbia analyzed the relationship between shiftwork and a pro-inflammatory diet using data from a nationwide sample of employed adults. Based on diet questionnaires, the researchers calculated a "dietary inflammatory index" (DII) for each individual. The greater the DII score, the more pro-inflammatory the diet.
With adjustment for other factors, shift workers had an elevated DII, compared to day workers. The difference was significant for rotating shift workers (those who worked varying shifts): average DII 1.07, compared to 0.86 for day workers.
Women had higher DII values than men. Among women, the DII was higher for evening or night shift workers compared to day workers: 1.48 versus 1.17.
Shiftwork has been linked to increased risks of disease, including high blood pressure, obesity, cardiovascular disease, and diabetes. Poor eating habits may contribute to some of these risks. Western-style diets with higher levels of calories and fats have been linked to increased inflammation, compared to Mediterranean diets high in fruits and vegetables.
The DII provides a way of measuring how "pro-inflammatory" a person's diet is. A recent study of police officers found a higher DII in officers doing shiftwork. The new study suggests a similar elevation in DII among shift workers in the general population.
"Inflammatory diets represent a target for behavioral interventions to reduce the health impacts of shiftwork," say the researchers. They add that interventions should address other important lifestyle factors as well, including physical activity, proper sleep and light exposure.
Source: Journal of Occupational and Environmental Medicine, February 2014.
Leslie’s Note: The following foods can help subdue inflammation in the body by promoting the production of anti-inflammatory immune compounds.
Eat oily fish. To increase your intake of DHA and EPA, aim to eat six to 12 ounces of oily fish per week. The best sources of these omega-3 fatty acids include salmon, herring, anchovy, mackerel and sablefish (e.g. black cod). (These fish are also low in mercury.)
If you don’t like fish, consider taking a fish oil supplement. Most capsules provide 300, 500 or 600 milligrams of DHA and EPA (combined). Liquid fish oils often contain 1300 milligrams of DHA and EPA per teaspoon.
Get your ALA. Alpha-linolenic acid, another omega-3 fatty acid, also regulates inflammation in the body. Women require 1.1 grams of ALA per day and men need 1.6 grams.
The best sources include flax oil (1 teaspoon = 2.4 grams ALA), ground flaxseed (1 tablespoon = 1.6 grams), chia seeds (2 tablespoons = 2.5 grams), walnuts (14 halves = 2.5 grams) and canola oil (1 tablespoon = 1.3 grams).
Snack on nuts. The anti-inflammatory properties of nuts are attributed to their polyunsaturated fat, magnesium and antioxidant content.
Include one ounce of nuts in your daily diet. Substitute nuts for less healthy snacks like cookies, candy, soft drinks, and refined starchy foods. One ounce of nuts isn’t that large – you’ll need to count out 8 Brazil nuts, 18 cashews, 14 walnut halves, 24 almonds or 28 peanuts.
Switch to monounsaturated fat. This type of fat found in olive oil, peanut oil, safflower oil and canola oil, helps shield the body from inflammation. Other sources of monounsaturated fat include avocado, almonds, hazelnuts, pistachios and peanuts.
Increase flavonoids. Natural compounds in fruit, vegetables, soybeans and tea, called flavonoids, also dampen inflammation. Flavonoid-rich fruit and vegetables include berries, cherries, red grapes, apples, citrus fruit, broccoli, kale and onions. Other good sources include green and black tea, dark chocolate, soybeans, edamame and tofu.
Take vitamin D. Among its many roles, vitamin D has anti-inflammatory effects in the body. In fact, research has shown that vitamin D deficiency is associated with higher levels of inflammation in adults.
Current vitamin D recommendations range from 600 to 2000 IU per day. In the fall and winter, when the sun isn’t strong enough to produce vitamin D in the skin, Canadians are advised to supplement with 1000 to 2000 IU vitamin D per day. The safe upper daily limit is 4000 IU per day. Speak to your health care provider about the right vitamin D intake for you.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.