Researchers wanted to know if adding extra salt to meals could help people who had gastric bypass surgery control their blood sugar better. They tested 11 people without diabetes by giving them meals with and without added salt on different days. The results showed that while extra salt didn’t dramatically change overall blood sugar levels, it did slightly lower the highest blood sugar spike after eating. This is interesting because it suggests salt might play a small role in how the body handles sugar after this type of surgery, but more research is needed to understand if this actually matters for people’s health.

The Quick Take

  • What they studied: Whether adding salt to a carbohydrate-rich meal helps control blood sugar levels in people who have had gastric bypass weight loss surgery
  • Who participated: 11 adults (average age 57 years old, mostly women) who had Roux-en-Y gastric bypass surgery and did not have diabetes
  • Key finding: Adding 2 grams of salt to meals slightly lowered the peak blood sugar spike after eating (from 8.3 to 7.8 mmol/L), but did not significantly change overall blood sugar control or the lowest blood sugar levels reached
  • What it means for you: If you’ve had gastric bypass surgery, adding a bit of extra salt to meals with carbohydrates might help prevent your blood sugar from spiking as high, though the effect is modest. However, this is a very small study, so talk to your doctor before making dietary changes, especially if you have high blood pressure or other health conditions

The Research Details

This was a small, carefully controlled experiment where 11 people who had gastric bypass surgery came to the lab on two different days. On one day, they ate a meal with extra salt added (2 grams, which is about 785 mg of sodium). On the other day, they ate the same meal without the extra salt. The researchers didn’t tell the participants which meal had the salt, but the participants knew they were being tested. Blood samples were taken before eating and at different times after eating to measure blood sugar and other hormones.

The study design is called a ‘crossover’ study, which means each person got both the salt and no-salt conditions. This helps researchers see the real difference because they’re comparing each person to themselves rather than comparing different groups of people. The researchers focused on measuring blood sugar levels at different time points and calculating the total amount of glucose in the blood over a three-hour period after eating.

This research approach is important because gastric bypass surgery changes how the body absorbs nutrients, including how it takes in sugar from food. The researchers wanted to test a theory from animal studies that adding salt might help the intestines absorb sugar better after surgery. By doing a controlled experiment where everything except the salt is the same, they can see if salt really makes a difference. This careful approach helps separate the effect of salt from other factors that might change blood sugar.

This study is a proof-of-concept study, which means it’s designed to test a new idea rather than prove something definitively. The sample size is very small (only 11 people), which is a limitation because results from small studies can be less reliable than larger ones. The study was ‘open-label,’ meaning the researchers knew which condition was which, though the participants didn’t always know. The study was randomized, meaning the order of the two meal tests was chosen randomly, which helps reduce bias. Because it’s small and preliminary, the results should be viewed as interesting but not conclusive.

What the Results Show

The main finding was that adding salt did not significantly change the lowest point that blood sugar reached after eating (3.7 mmol/L with salt versus 3.5 mmol/L without salt). This was the main outcome the researchers were looking for, and the difference was too small to be meaningful.

However, the researchers did notice that the highest blood sugar level after eating was slightly lower when salt was added (7.8 mmol/L with salt versus 8.3 mmol/L without salt). While this difference is small, it was statistically significant, meaning it’s unlikely to have happened by chance. This suggests that salt might help prevent blood sugar from spiking as high after meals, even though it doesn’t change the overall pattern of blood sugar control.

When the researchers looked at the total amount of glucose in the blood over the three hours after eating, there was no meaningful difference between the salt and no-salt conditions. This means that while the peak might be slightly lower with salt, the overall blood sugar control throughout the day appears to be similar.

The researchers also measured insulin (the hormone that helps control blood sugar), C-peptide (a marker of how much insulin the body is making), and GLP-1 (a hormone that affects blood sugar and appetite). None of these hormones showed meaningful differences between the salt and no-salt meals. This suggests that salt doesn’t change how much insulin the body produces or how the body’s hormonal system responds to meals after gastric bypass surgery.

Previous animal studies suggested that salt might help the intestines absorb glucose better after gastric bypass surgery by activating special transporters in the gut. This human study provides some evidence that salt might have a small effect on blood sugar peaks, which is consistent with the animal research. However, the effect is much smaller than the animal studies suggested it might be, and it doesn’t affect the overall blood sugar control or hormone responses. This suggests that while the theory has some merit, the practical importance of salt for blood sugar control after surgery may be limited.

This study has several important limitations. First, it included only 11 people, which is a very small number. With such a small group, the results might not apply to everyone who has had gastric bypass surgery. Second, the study was short-term, looking at blood sugar for only three hours after eating, so we don’t know if the effects would continue throughout the day or over weeks and months. Third, all participants were people without diabetes, so the results might be different for people who have diabetes. Fourth, the study only tested one amount of salt (2 grams), so we don’t know if more or less salt would have different effects. Finally, the study was done in a controlled lab setting with a specific meal, so real-world eating might produce different results.

The Bottom Line

Based on this small study, there is weak evidence that adding salt to carbohydrate-rich meals might slightly reduce blood sugar spikes after gastric bypass surgery. However, the effect is small and may not be clinically important. If you’ve had gastric bypass surgery, you should not make major changes to your salt intake based on this single study. Instead, follow your doctor’s recommendations about salt intake, especially if you have high blood pressure or heart disease. More research with larger groups of people is needed before making specific dietary recommendations.

This research is most relevant to people who have had Roux-en-Y gastric bypass surgery and are concerned about blood sugar control. It may be of interest to bariatric surgeons and dietitians who work with post-surgery patients. People with diabetes should not assume these results apply to them, as the study only included people without diabetes. People with high blood pressure or heart disease should be cautious about increasing salt intake without talking to their doctor first.

If salt does help reduce blood sugar spikes, the effect would happen immediately after eating the meal, not over days or weeks. This study only measured blood sugar for three hours after eating, so we don’t know about longer-term effects. It would take larger, longer studies to determine if this small effect on peak blood sugar has any real health benefits over time.

Want to Apply This Research?

  • If you’ve had gastric bypass surgery, track your blood sugar readings (if you monitor them) along with the salt content of your meals for 2-4 weeks. Note the peak blood sugar readings after meals with varying salt amounts to see if you personally notice a pattern. Record the time of day, meal composition, and salt added to identify any personal trends.
  • If interested in testing this for yourself, try adding a small pinch of salt (about 1/4 teaspoon) to one carbohydrate-rich meal per day for two weeks while tracking how you feel and any blood sugar readings. Compare this to a two-week period without added salt. Keep notes on energy levels, hunger, and any blood sugar changes you notice.
  • Create a simple daily log tracking: (1) meals eaten with estimated salt content, (2) any blood sugar readings if available, (3) energy levels and hunger throughout the day, and (4) any digestive symptoms. Review weekly to identify personal patterns. Share results with your healthcare provider before making permanent dietary changes.

This research is preliminary and based on a very small study of 11 people. The findings should not be used to make medical decisions without consulting your healthcare provider. If you have had gastric bypass surgery, diabetes, high blood pressure, heart disease, or kidney disease, talk to your doctor or registered dietitian before making changes to your salt intake. This study does not provide enough evidence to recommend adding salt to meals for blood sugar control. Individual responses to dietary changes vary, and what works for one person may not work for another. Always follow your doctor’s personalized dietary recommendations.