Not all oat milks are the same. Some have more additives than others. But one thing rings true time and time again: nearly every oat milk option has a significantly higher amount of carbs than its counterparts.
Depending on the brand, one cup of unsweetened oat milk can have as many as 17 grams of carbs—significantly more than almond milk, which has just 1 to 3.5 grams. Not only that, but a large portion of those carbs are starch: one cup of whole oats (not in milk form) consists of 57.9% starch (1).
The issue with this is that many modern starches are refined, meaning that they can cause blood sugar elevations—even if they’re classified as “healthier” complex carbs (2). Blood sugar spikes can make you feel tired, cranky, and downright hungry (3). A diet heavy in refined starch can increase your risk of heart disease and type 2 diabetes, so it’s important to consider the overall dietary pattern (4, 5, 6, 7).
An additional concern around oat milk is that many oat products on the market have been found to be associated with Roundup Weed Killer. You might recognize Roundup’s name from the many public-facing lawsuits filed against its parent company for the product’s links to cancer, however it is important to note that in many of these cases it is workers who were in close contact with spraying glyphosate for many years (11).
Roundup’s most well-known ingredient is glyphosate. It’s the most widely used herbicide in the world (12). In 2015, the World Health Organization classified glyphosate as “probably carcinogenic to humans” (13). Research has linked glyphosate to cancer, neurological diseases, birth defects, changes in gut bacteria, and endocrine disruption (14, 15, 16, 17, 18). In addition to glyphosate, Roundup can contain heavy metals, including arsenic, which has been linked to cancer, heart disease, and development issues in children (19, 20).
A 2021 study found glyphosate in oat products, including popular brands like Quaker and Nature Valley (21). And just this year, a consumer study found that 2 of 13 popular oat milk brands contained detectable levels of glyphosate or arsenic (22).
The study found traces of glyphosate and arsenic in Malk Organic Oat Milk. It also found glyphosate in Silk Extra Creamy oat milk. Some experts attribute these ingredients to something called pre-harvest desiccation, a money-saving move in which Roundup is sprayed on crops late in the season to speed up the crops’ drying out.
While many commercially sold oat milks are fortified with vitamin B, vitamin D, and vitamin E—you can get those vitamins elsewhere without dealing with the beverage’s potential downsides (23).
