US Fast Food Contains Excessive Levels of Sodium

Meals from fast-food chains contain excessive amounts of salt, a new study has shown. Over half of all purchases exceeded the 1500-mg daily limit of sodium advised for most Americans, and this rose to 84% of meals when only fried-chicken outlets were considered. Only one in 36 purchases met the FDA “healthy” sodium limit (600 mg) for meals….

Christine M. Johnson (Cardiovascular Disease Prevention and Control Program, New York City Department of Health and Mental Hygiene) and colleagues reported in the Archives of Internal Medicine that, “This study extends analyses of the nutritional content of fast food from calorie to sodium content and shows that fast food is high in sodium as well as calories.”

The widespread consumption of fast food “contributes to current high levels of daily sodium intake in the US, higher blood pressure, and the resulting burden of cardiovascular disease,” so reducing sodium levels in such foods is “a public-health priority,” they urge.

In their study, Johnson et al collected data from noon to 2 pm on weekdays from March to June 2007; adults who bought a meal from one of 167 locations representing 11 fast-food chains across the five boroughs of New York City answered a brief survey and provided their purchase receipt in exchange for a $2 metro card. Nutrition information posted on company websites as of March 1, 2007, was used to determine sodium content.

The final sample size was just over 6,500 meals; each meal contained, on average, 1751 mg of sodium; 20% had more than 2300 mg. Fried-chicken chains were the biggest culprits, with 55% of their meals containing more than 2300 mg.

And excess sodium was not simply the result of large portion size, say Johnson et al; they also calculated sodium density, defined as mg of sodium per 1000 cal. The sandwich and fried-chicken outlets and one pizza chain, Papa John’s, were the worst culprits in terms of the sodium density of their foods.

Mean sodium, mean calories, and mean sodium density of meals at 11 New York City fast-food chains by collection of customer receipts

Fast-food chain	Mean sodium, mg	Mean cal	Mean sodium density,  mg/1000 cal
Burger King	1685	1008	1727
McDonald’s	1477	908	1782
Wendy’s	1631	907	1885
Sandwich
Au Bon Pain	1553	608	2842
Subway	1883	768	2627
Fried chicken
KFC	2397	958	2504
Popeye’s	2497	1050	2418
Pizza
Domino’s	2465	1550	1545
Papa John’s	1561	652	2443
Pizza Hut	2272	1017	2233
Tex-Mex
Taco Bell	1849	909	2093

The researchers say the strengths of their study include the use of receipts of meals purchased, rather than reliance on patron self-report, and the large sample of patrons from randomly selected locations. Participants were not asked about salt added at the table, however, potentially underestimating the sodium content per meal.

“Our findings support the need for the fast-food industry to focus on reducing sodium levels across product lines,” they conclude. “Government, public-health, and industry involvement to accelerate food reformulation will reduce blood pressure and save lives.”

Dr. Henry Black,  president of the American Society of Hypertension, commented that, “I am not surprised. I don’t think the public really knows how much salt is in these foods.” And he agrees that urgent attempts should be made to reduce the sodium content in such foods. “Experience in the UK and other countries has shown that you can reduce the amount of salt in processed foods and restaurant foods without anybody complaining.”

Johnson et al note that current US recommendations are for adults to limit sodium intake to less than 2300 mg per day, and several groups — blacks, middle-aged and older people, and those with hypertension, who together make up 69% of the adult population — are advised to cap intake at 1500 mg per day. Despite these suggestions, most adults consume an average of 3500 mg of sodium per day, with more than 75% of dietary sodium coming from packaged and restaurant foods.

Black cautions that it will be important as things move forward on this issue in the US to avoid confusion among the public between salt and sodium. “Is the limit 6000 mg of salt a day, is it 2300 mg of sodium? We have to be careful of this, and maybe the people who make recommendations should select one or the other. Perhaps it’s better for the public to call it salt?”

Moves are now afoot in the US to emulate the efforts of other countries, which have successfully reduced the amount of salt in processed foods by working together with the food and beverage industries.

Just last week, the Institute of Medicine issued a report advising the FDA that it should set stricter federal standards for the amount of salt that food manufacturers, restaurants, and food-service companies can add to their products, and New York City has been at the forefront of a countrywide campaign — the National Salt Reduction Initiative — which aims to cut the salt content in bought foods by 25% over five years. The American Medical Association has also called on industry to reduce the sodium content of processed products by 50%; such a reduction would save “tens of thousands of lives each year” and save almost $20 billion in healthcare costs annually, say Johnson et al.

Johnson CM, Angell SY, Lederer A, et al. Sodium content of lunchtime fast food purchases at major US chains. Arch Intern Med 2010; 170:732-734. PubMed