A just-published study shows that drinking either sugared or artificially-sweetened drinks is associated with increased risk for diabetes (Am J Clin Nutr, Jun 28, 2017). Of 64,850 post-menopausal women followed for 8.4 years, 4675 developed diabetes. Women who drank two 12-ounce cans (355 mL)/day of sugar-sweetened beverages had a 43 percent increased risk for developing diabetes, while those who drank the same amount of artificially-sweetened beverages had a 21 percent increased risk of developing diabetes. Replacing one can of artificially sweetened beverage with water reduced diabetes risk by five percent, and replacing one can of sugar sweetened beverage with water reduced the risk by 10 percent.

Artificial Sweeteners May Change Colon Bacteria
Another team of researchers in Israel showed that artificial sweeteners (aspartame, saccharin and sucralose) raise blood sugar levels both in mice and in humans by changing the intestinal bacteria to favor those that appear to prevent the body from responding to insulin (Nature, September 17 2014).See Gut Bacteria Linked to Diabetes

The researchers found both lean and obese mice consuming the artificial sweeteners saccharin, sucralose or aspartame in their water over 11 weeks developed glucose intolerance, while those consuming plain water or water with glucose or sucrose did not. After a meal, mice given artificial sweeteners had blood sugar levels that rose higher and stayed higher longer.

The mice that were given artificial sweeteners took in the same amounts of food and drinks and did the same amount of exercising (measured by how much they walked) as those not given the artificial sweeteners. Since the artificial sweeteners were the only variable, the authors felt that the higher blood sugar levels were caused by the artificial sweeteners and not by anything else. They found that:
• Mice given saccharin developed new and different bacteria in their colons
• When the mice taking the artificial sweeteners were given antibiotics, their blood sugar levels dropped to normal. The authors felt this showed that the artificial sweeteners raised blood sugar levels by changing the intestinal bacteria, since killing the new colon bacteria caused blood sugar levels to drop to normal.
• Mice who had never taken artificial sweeteners and had normal blood sugar levels developed elevated levels of blood sugar after being given gut bacteria from mice fed large amounts of artificial sweeteners.
• The new artificial-sweetener-induced-intestinal bacteria appeared to break down nutrients in food so that the mice absorbed more calories from the food they ate.
• Giving stool from the people who took artificial sweeteners to bacteria-free mice caused the mice to develop glucose intolerance. Giving stool from non-diabetic humans who never took artificial sweeteners did not raise blood sugar levels in mice. Altering gut bacteria pathways may stimulate fat tissue to prevent obesity.

Similar Results in Humans
The authors found that 381 people who were not diabetic but took artificial sweeteners regularly had higher blood sugar levels than those who took no artificial sweeteners.
• Seven healthy adults who had not taken saccharin previously were given 120 mg/day of saccharin. This is the Food and Drug Administration's maximum acceptable dose (5 mg/kg body weight). In five weeks, four of the seven developed higher blood sugar levels, a decreased ability to respond to insulin and a change in their gut bacteria.
• The 381 non-diabetic people who used artificial sweeteners regularly for a long time had more markers of diabetes: greater waist circumference (abdominal obesity), waist to hip ratio and blood levels of glucose after fasting, and decreased ability to respond to insulin.
• Those who used artificial sweeteners had a different gut bacteria composition from people who did not consume artificial sweeteners.

My Recommendations
Recent research strongly suggests that taking in large amounts of any sugared drinks, including fruit juices, is associated with increased risk for weight gain and diabetes. The data strongly suggest that sugared drinks are more harmful than those that contain artificial sweeteners.

Recent research also suggests that artificial sweeteners increase risk for weight gain and diabetes in mice. However, we do not have enough data to prove that artificial sweeteners cause diabetes in humans. Criticism of studies on artificial sweeteners in humans centers on the fact that people who are overweight or diabetic may be more likely to use artificial sweeteners, so it is not possible to say that artificial sweeteners have any role in causing overweight or diabetes. Furthermore, we have suggestive data on saccharin but do not have strong data on any of the other artificial sweeteners. If artificial sweeteners do indeed increase risk for diabetes, I believe that they probably do so by changing bacteria in the colon. 

Checked 7/1/18