May 30, 2016

High Salt Consumption Can Cause Weight Gain

One group publishes a study and another group answers with their study. This group takes a different approach and talks about weight gain being caused by salt, actually too much salt.

Researchers say the studies - published in the Journal of Nutrition and Chemical Senses - support calls for the food industry to lower the salt, or sodium, intake of food products. Both studies were conducted by Prof. Russell Keast and colleagues from Deakin University in Australia.

While you may not be heavy handed with the salt shaker, it is processed foods and restaurant meals that are the primary culprit, accounting for more than 75% of our sodium intake.

Previous research from Prof. Keast and colleagues, including a study reported by Medical News Today earlier this year, suggested that individuals who are more sensitive to the taste of fat are more likely to eat fatty foods, putting them at greater risk of obesity.

Their latest studies build on that research, suggesting that the amount of salt in a certain food may influence how much we eat, as salt could mask our fat preferences.

For the first study, the team set out to investigate the effects of salt on the taste of fat and food preference.

The researchers enrolled 49 healthy participants aged 18-54 and asked them to taste a variety of tomato soups that had four different fat concentrations (0%, 5%, 10% and 20%) and five different salt concentrations (0.04% - no added salt - 0.25%, 0.5%, 1% and 2%).

Fast facts about salt
  • Grains, meat and processed poultry, soups and sandwiches are top contributors to Americans' salt intake
  • A single slice of bread can contain anywhere from 80-230 mg of salt
  • One slice of pizza can contain up to 730 mg of salt.

After consuming the soups, participants were asked to rank the pleasantness and desire to eat each soup, as well as the perceived fattiness and saltiness of each soup.

Fat taste sensitivity among participants was measured by their ability to taste oleic acid - a fatty acid in vegetable fats and oils - at various concentrations in long-life skimmed milk.

The researchers found that salt is a major player in the pleasantness of a food, with rating of food pleasantness varying greatly dependent on different salt contents; a salt concentration of 0.25-5% rated as most pleasant.

For the second study, the team wanted to examine the effect of salt on food intake. They enrolled 48 healthy adults aged 18-54. As in the first study, participants' fat taste sensitivity was determined by their ability to taste oleic acid.

Over a 6-day period, participants were required to attend four lunchtime sessions. Lunches consisted of elbow macaroni and sauce, and sauces contained varying concentrations of fat and salt.

The researchers measured subjects' food intake over the study period, and participants were required to rate the pleasantness of each food. The team found that participants consumed around 11% less food and energy when their lunches contained low salt and high fat.

"However, when given high-salt high-fat foods, those same subjects consumed significantly more food and energy," explains Prof. Keast. "Those who were less sensitive to fat consumed the same amount in each salt condition." Overall, the authors say their studies indicate that salt may interfere with the body's biological processes that stop us from eating too much.

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