Probiotics have been big news for the past decade. While these beneficial bacteria are most commonly used to treat a host of digestive disorders, they have also been positively associated with everything from allergies and liver disease to yeast infections, and even cancer.
There have even been several lab and animal studies showing that probiotics can help lower cholesterol. However, when it comes to probiotics and cholesterol levels in humans, the research is less conclusive. This has been partly attributed to types and dosages of probiotics and the varying states of health of participants, as well as the design, sample size and study length.
Given this, researchers from Iran set out to address several of these issues in a new study looking at the effectiveness of probiotics in lowering cholesterol levels in people with type-2 diabetes.
Power-Packed, Beneficial Yogurt
Researchers set up a double-blind, randomized study with 60 participants. All were between the ages of 30 and 60, had a BMI of less than 35 (35 or greater is considered morbidly obese), and had been diagnosed with type-2 diabetes for at least one year.
They also had LDL cholesterol levels of 2.6 mmol/L (or 100 mg/dL) or greater. LDL levels of less than 2.6 mmol/L are considered optimal, and 2.6 mmol/L to 3.3 mmol/L indicates a slightly increased risk for cardiovascular disease.
Researchers randomly divided the participants into two groups. The first group ate 300 grams of conventional yogurt a day for six weeks. This is the equivalent of 10.5 ounces. (The average container of yogurt is 6 ounces.) This yogurt contained naturally occurring probiotics (Lactobacillus bulgaricus and Streptococcus thermophilus).
The second group also ate 300 grams of the same yogurt daily for six weeks, but in addition to the naturally occurring probiotics, their yogurt had been fortified with additional Lactobacillus acidophilus and Bifidobacterium lactis. Both yogurts contained 2.5 percent fat and had similar taste and appearance.
Both groups were instructed to maintain their other dietary habits and lifestyle. They were also told to avoid other yogurt and products containing probiotics.
At the beginning and end of the study, researchers noted the weight and BMI of all participants. They also took fasting blood samples of all participants, measuring their total cholesterol, triglyceride, HDL (good) and LDL (bad) levels, as well as the ratios between total cholesterol and HDL, and the ratios between LDL and HDL cholesterol.
Good Bugs, Good Health
At the end of the study period, researchers found that, first and foremost, there was excellent compliance, meaning that the participants happily ate the yogurt every day for the six weeks. Additionally, there were no adverse effects or symptoms associated with the yogurt.
On the cholesterol front, there was a significant difference between the two groups. Those in the fortified yogurt group had a 4.5 percent decrease in total cholesterol and a 7.5 percent decrease in LDL cholesterol, as compared to those in the regular group.
While triglycerides and HDL levels did not change in the fortified group, HDL levels did significantly decrease in the control group. (The study authors did not comment on what may be the reason behind the decrease in good cholesterol levels in the non-fortified group.)
Additionally, the fortified group saw a 5.4 percent reduction in their total cholesterol/HDL ratio, as well as an 8.6 percent decrease in their LDL/HDL ratio.
This is great news, as your cholesterol ratio can be a powerful indicator of cardiovascular risk. As a rule, your ratio is determined by dividing your total cholesterol by your HDL. So, if your total cholesterol is 160 and your HDL is 40, your ratio would be 4:1.
The American Heart Association suggests that you keep your ratio at or below 5:1, but notes that 3.5:1 is ideal. Therefore, the smaller the gap in the ratio, the better. This means that any decrease or reduction in your cholesterol ratio benefits your cardiovascular health.
Researchers concluded, “This trial showed that consumption of probiotic yogurt containing L. acidophilus La5 and B. lactis Bb12 could decrease serum [total cholesterol] and LDL [cholesterol] concentrations in type 2 diabetic people.” They go on to suggest that probiotics-rich yogurt may help decrease cardiovascular disease risk factors in people with type-2 diabetes.
An Interesting Note
One very interesting note from the study was that previous research has indicated that probiotics supplements were not effective in lowering cholesterol. For some reason, the dairy found in the yogurt seemed to be a more effective way of delivering the probiotics’ benefits. One possible reason for this may be that freeze-drying probiotics in order to encapsulate them may delay their ability to become metabolically active in the intestine.
The news just keeps getting better and better when it comes to probiotics, and yogurt specifically. Your best bet is to aim for one to two servings of yogurt daily. But be cautious in your selection. Unlike men (and women!), not all yogurt is created equal.
When buying dairy-based yogurt, try to choose organic and plain/unsweetened. If you need a flavor boost, try liquid stevia (a calorie-free sweetener). There are even delicious flavored liquid stevias, including vanilla, English toffee and chocolate raspberry. That way you get the benefits of the yogurt without the sugar hit.
And if lactose is a concern, try a coconut milk based yogurt. It is a delicious and heart-healthy alternative to dairy!
 Ejtahed, HS et al. Effect of probiotics yogurt containing Lactobacillus acidophilus and Bifidobacterium lactis on lipid profile in individuals with type 2 diabetes mellitus. J Dairy Sci. 2011 Jul;94(7):3288-94.
 Greany, KA et al. Probiotic capsules do not lower plasma lipids in young women and men. Eur J Clin Nutr. 2008;62:232-7.
 Lewis, SJ and Burmeister, S. A double-blind placebo-controlled study of the effects of Lactobacillus acidophilus on plasma lipids. Eur J Clin Nutr. 2005;59:776-80.