Once upon a time, there was a little oat.

This little oat brought joy and happiness to the people. He gave them warm breakfast porridge, date squares, and now, in the 21st century and without the necessary organs, oat milk.

While the little oat was living its best life, suddenly, haters started throwing shade. Hurtful things like this:

Should the little oat pack up its bags and hop on the next train to Clarksville? Well, let’s see what the science says.

What’s an oat?

An oat is a grain. Here’s what it looks like.

Why do people hate the little oat?

A lot of the hate comes from rising blood sugar after eating oats. But saying it’s bad because it causes blood sugar to rise doesn’t mean anything without any other context. As we’ll see, many of these opinions are half-truths promoting a particular viewpoint.

Key terms

Meta-analysis- Meta-analysis is the statistical combination of results from two or more separate studies. Think of this as the bigger picture. 

Systematic review- A systematic review is defined as “a review of the evidence on a clearly formulated question..”Another way of looking at the bigger picture. 

Randomized control trial (RCT)- A study design that randomly assigns participants into an experimental group or a control group. Considered the ‘gold standard’ for studying a particular outcome. 

Health benefits

Blood sugar

We’ll start here since most of the hate comes from here. 

One meta-analysis compared oat processing with blood glucose response vs. refined grains. As predicted, the more “whole” and intact the oat, the lower the postprandial blood glucose response (whole vs thick flaked vs. thin/quick/instant). However, thin/quick/instant did not show an improvement over refined grains. 

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Another meta-analysis of oat intake for type II diabetics found that oat intake correlated with lower HbA1c and fasting blood glucose vs control meals. Basically, oats were shown to improve markers of diabetes. Photos below for the graphically inclined.  

The bottom line. Buy whole grain or large flaked oats over thin or quick or instant oats. Also, replace your refined grain sources with whole or large flake oats or other whole grain sources.

Gut health

Short-chain fatty acids (SCFA) are by-products of the bacteria in our gut. They digest the fiber we eat and create these molecules that may do good things for the body- like reducing inflammation and maintaining the intestinal barrier in our gut (specifically the colon). People suffering from IBD (like Crohn's and ulcerative colitis) may have an altered amount of short-chain fatty acids relative to people without the disease. 

One systematic review found that oats increased the total bacterial count for 2 beneficial human strains: Lactobacillus and Bifidobacterium in healthy people and those with celiac disease. They also found a higher amount of short-chain fatty acids and improved gut permeability with oat intake. In addition, some studies found no change in GI symptoms associated with oat intake, which didn't affect the quality of life. However, others found a worsening of symptoms with oat intake. 

One randomized control trial found that consuming oat bran increased SCFA compared to the control diet (wheat products). In the oat bran group, the study also found a decrease in abdominal pain and indigestion from baseline compared to control. Keep in mind that the intervention consumed more fiber, and wheat products are a common FODMAP food, which may cause gastric symptoms in some people. Oats are not. 

The bottom line. Gastrointestinal issues are highly variable in their cause and severity. Therefore, although oat intake may benefit or improve gut health, what works for one person might not work for another.    

Cardiovascular health

Consider a box of cheerios.

The bottom right corner of the box claims that “oat fiber helps lower cholesterol.” The oats-for-heart-health slogan has been around for some time, but does it ring true in 2022?

One systematic review and meta-analysis showed that oats improve total cholesterol levels, LDL cholesterol, body mass index and waist circumference. So, lots of cardiovascular benefits for the oat groups compared to control/non-control groups. For this study, however, it should be noted that most study participants were men and that slightly under 50% of RCTs compared isocaloric diets. And we know that weight loss can dramatically improve blood lipids.

More interestingly, however, is the type of fiber within oats- beta-glucan.

Beta-glucan is a soluble fiber found in certain grains, but most predominantly in oats and barley. This compound is thought to contribute to the lipid improving effect of oats. 

Another systematic review and meta-analysis showed that 3.5g of beta-glucan significantly reduces LDL and non-HDL cholesterol, as well as apoB. For reference, there is around 3-8g of beta-glucan in 100g of oats. 

A quick note about apoB. ApoB is a marker for cardiovascular disease. It’s the closest thing we have right now to actually causing it. So keeping this in check is very important for heart health.

In this meta-analysis, in particular, there was high heterogeneity primarily due to the methods of attaining beta-glucan levels in each respective trial. With that said, apoB lowering concentrations had the least variance. All in all, the bigger picture looks suitable for oats improving blood lipid levels. 

The bottom line. Oats seem to show quite a few cardiovascular benefits, especially for apoB.

What about Cheerios?

I should tell you why I eat Cheerios since I’m a Cheerio shill. Here is my case.

By the way, I, and this article, are not sponsored by Cheerios.

• Cheerios taste good.

• Cheerios are made from whole grain oats. There is robust evidence linking whole grains to numerous health benefits.

This review suggests that there is some evidence for dietary whole grain intake to be beneficial in the prevention of type 2 diabetes, cardiovascular disease, and colorectal, pancreatic, and gastric cancers. The potential benefits of these findings suggest that the consumption of 2 to 3 servings per day (~45 g) of whole grains may be a justifiable public health goal.

According to Cheerios.com, 1 serving of cereal contains 14g of whole grains. 31% of your daily whole grain intake. 

• As we can see from above, oats are highly likely to benefit general health.

• They are low in calories, saturated fat, and a source of fiber. For those following a low FODMAP eating plan, oats, and foods made from oats like Cheerio’s, could be an option for those people.

A quick note…

I don’t see RD’s or MD’s or nutritionists recommending someone eat a cup of oats independently. I certainly wouldn’t- I probably wouldn’t feel good after either. Instead, throw some nut butter, fruit, nuts or seeds with your oats, and consider 1/4 to 1/3 cup of oats (although this could differ depending on the circumstance and goal). Also, add a protein source with your oats. A lean piece of meat, eggs, a protein shake- you name it. Make oats a part of your meal instead of the staple.

In conclusion

I think the evidence supporting oat intake is pretty robust, particularly for cardiovascular health and promoting proper blood sugar levels. The evidence is less robust for gut health, however oats may have a beneficial effect.

For those looking to add oats into their diet, I suggest getting whole oats or buying thick flaked over thin, quick, instant oats. 

Check out this link for oat recipes!

References

https://academic.oup.com/jn/article/151/2/341/6029140?login=false

https://pubmed.ncbi.nlm.nih.gov/26690472/

https://academic.oup.com/jn/article-abstract/151/10/3075/6364878?redirectedFrom=fulltext&login=false

https://pubmed.ncbi.nlm.nih.gov/31498864/

https://www.frontiersin.org/articles/10.3389/fendo.2020.00025/full

https://academic.oup.com/crohnscolitis360/article/2/1/otaa005/5735017

https://pubmed.ncbi.nlm.nih.gov/34977959/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3236515/#:~:text=Beta%20glucan%20(%CE%B2%2Dglucan),obesity%20is%20being%20continuously%20documented.

https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/effect-of-oat-glucan-on-ldlcholesterol-nonhdlcholesterol-and-apob-for-cvd-risk-reduction-a-systematic-review-and-metaanalysis-of-randomisedcontrolled-trials/60A75CB215602240E9363D49DCB690ED

https://www.sciencedirect.com/science/article/abs/pii/S1556370716300736