Tag Archive for: propionate

SFCA, Sodium Intake, and High Blood Pressure

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Researchers in the United Kingdom recruited people with elevated systolic and diastolic blood pressure for a randomized, placebo-controlled, crossover study on diet and blood pressure. The scientists put all 145 subjects on a low-sodium diet for six weeks. Half the subjects was given a placebo while the other half was given a slow-release sodium supplement. After six weeks, the subjects were crossed over to the other group for another six weeks. The objective was to see if sodium intake impacted the microbiome and short-chain fatty acids (SCFA) production to reduce blood pressure.

In a perfect world, researchers would take stool samples under all conditions to test for changes in microbe content, but that approach is expensive and time-consuming. Instead they chose to monitor changes in SCFA because they’ve been associated with blood pressure.

Researchers found that while taking the placebo, subjects on the low-sodium diet saw all SCFA increase; 2-methylbutyrate, butyrate, hexanoate, isobutyrate, and valerate were significantly increased. The increases in SCFA were associated with reductions in blood pressure and arterial-wall stretchability.

What does it mean? We’ve known for decades that sodium plays a role in blood pressure. This study demonstrated that sodium reduction directly increased the production of SCFA, which then lowered blood pressure. What we don’t know is the specific beneficial microbes affected or exactly how sodium negatively impacts them. Research continues and I’m sure we’ll find that out eventually.

The Bottom Line

On the other hand, it may not be necessary to find out. Scientists like me always want to know the specific bacteria and the mechanism by how it works. We know that fluid retention is involved somewhere. But we already know that if we reduce sodium, we’ll positively impact our blood pressure. We also know that fiber is the essential food for these SCFA-producing bacteria in our microbiome. If we focus on a more fiber-rich diet as well as take a fiber supplement, we may be able to increase our odds of reducing blood pressure without medication. If we need the meds, we take them, but if we can do it by feeding our microbiome, that’s even better.

What are you prepared to do today?

        Dr. Chet

References:
1. Hypertension. 2020;76:73–79.
2. Benoit Chassaing, Andrew T. Gewirtz, in Physiology of the Gastrointestinal Tract (Sixth Edition), 2018.

Health Benefits of SCFA

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Let’s continue our look at short-chain fatty acids (SCFA) and what they do besides produce energy. Most of these are observational in nature; by that I mean when SCFA go up or down, effects are observed. What we don’t know at this point is why.

For example, when diabetic animals are given the SCFAs acetate and propionate, they maintain better glucose control. That means that adding SCFA to their diet can improve their ability to maintain blood sugar levels. Wait a second; is this the same acetate that’s found in vinegar? Yes. The problem is that the studies don’t provide consistent results.

The same is true for fat storage. When SCFA levels go up, fat storage appears to go down, but drinking vinegar doesn’t necessarily provide that benefit. Observational studies show that as SCFA levels made by the body go up, fat storage goes down. That can prevent weight gain, but we don’t know whether it causes weight loss. The same is true for cholesterol levels; SCFA are associated with lower cholesterol levels.

The problem is that we don’t know the precise mechanisms yet. In other words, what does making SCFA do to the metabolic systems in the body? To the genes? Or receptors for various functions? That’s what scientists are working on. Further, exactly what type of bacteria produce the right SCFA? There’s general agreement that Bifidobacteria produce acetate and propionate when fermenting fiber, but which Bifidobacterium? There are over 50 varieties. Maybe more than one—they may interact in sequence. We don’t know at this point.

What role do SCFA have in controlling blood pressure? Does sodium also have an impact on SCFA production? We’ll take a look at a recent study on Saturday.

What are you prepared to do today?

        Dr. Chet

References:
1. Benoit Chassaing, Andrew T. Gewirtz, in Physiology of the Gastrointestinal Tract (Sixth Edition), 2018.
2. Front Microbiol. 2016; 7: 925. doi: 10.3389/fmicb.2016.00925

Short-Chain Fatty Acids: DIY Nutrition

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Short-chain fatty acids (SCFA) are critical to your health and well-being, yet you may not really know where they come from or what they do. In my opinion, the most interesting thing about SCFA is that they’re not generally found in our diet; we make them ourselves! We do that when bacteria in the microbiome work to ferment digestible fiber.

By definition, SCFA contain less than six carbon molecules. The three you may have heard about are acetate, propionate, and butyrate. SCFA can provide us with up to 10% of our energy needs. They’re especially important to colonocytes, a type of endothelial cells of the large intestine that need energy to digest and absorb food that we use to produce the rest of the energy we need.

I’ll cover what else SCFA do on Thursday. In the meantime, one way to increase the production of SCFA is to get more fiber, whether from foods or supplements. It’s especially important after a course of antibiotics; research has shown that after the microbiome is upset by antibiotics, the production of SCFA can be impaired, which impacts many biological processes.

The monthly Insider Conference Call is tomorrow night at 9 p.m. Eastern Time. You can still participate by becoming an Insider by 8 p.m. tomorrow night. If you have questions about COVID-19 or any other health topic, this is your chance to get answers. I hope to talk with you then.

What are you prepared to do today?

        Dr. Chet

Reference: Benoit Chassaing, Andrew T. Gewirtz, in Physiology of the Gastrointestinal Tract (Sixth Edition), 2018.