Vitamin C in Your Produce: What TeakOrigin Data Reveals

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At TeakOrigin, our goal is to use data to understand what’s inside the food we buy and eat. One thing we have learned is that you can’t tell the nutritional value of two identical tomatoes by looking at them on the grocery store shelf. They may look the same, but one could have a lot less vitamin C and other nutrients, and how is one to know?

This is why we’re using rigorous, scientific tests to see what’s inside our produce. And by doing so, we’re able to see and understand food in ways we never could before.

Here are some examples of questions we can now ask about our food, related to vitamin C.

Which Foods Have More Vitamin C Than USDA Guidelines?

Our data at TeakOrigin showed that all the foods we measured over a six-month period in both Los Angeles and Boston for vitamin C had higher levels of vitamin C than the United States Department of Agriculture (USDA) guidelines. However, strawberries outperformed the USDA the most, with 2.5 times as much vitamin C than what’s claimed on the label.

“Many consumers don’t realize how much vitamin C is in strawberries to begin with, and our data show that vitamin C in strawberries is even better than the label claims,” says Brent Overcash, co-founder, and CEO of TeakOrigin.

If you can’t find strawberries, spinach is your next best option for getting more vitamin C. We saw that spinach contained 44.7 mg (per 100 g) of vitamin C, which is 60% more on average than the label claims.

TeakOrigin Vitamin C scores (in orange) exceeded USDA guidelines

Which Food Item Is Most Likely to Underperform in Delivering Vitamin C When You Buy It?

According to our data, blueberries had the highest likelihood of having a low score and delivered less vitamin C than they’re supposed to. 49% of the blueberries we sampled (almost half) scored less than 75%, which means they delivered less than 75% of the vitamin C that is expected based on the USDA guidelines.

While we don’t know exactly why vitamin C was low in half of our blueberry samples, we do know that vitamin C levels decrease as blueberries age, and the way they’re stored also affects them. Temperature, light, and oxygen can all influence the vitamin levels in berries.

If you are looking for foods that maintain the most vitamin C when you buy them, bananas and spinach are your best bet. Only 9.7% of bananas and 10.6% of spinach samples had vitamin C scores under 75%.

Blueberries had the highest likelihood of having a low Vitamin C score (in green), while spinach and bananas had the lowest.

Which Grocery Store Had the Most Consistent Vitamin C Scores in Strawberries?

Target and Walmart showed the least amount of variance in vitamin C in strawberries. (Variance shows how far apart numbers are spread out compared to the average.) This means that both stores had the most consistent levels of vitamin C in strawberries.

The variance was +/-1.1% for both stores, while other stores had a variance that went up as high as +/2.0%. Take a look at our p-test graphs below and notice that Target and Walmart had the least stretched out graphs:

Variance shows how far apart numbers are spread out compared to the average — Target and Walmart had the least variance in strawberry Vitamin C

When Were Vitamin C Levels the Highest in Tomatoes?

Based on our data from January through March in Los Angeles and Boston, tomatoes had the most vitamin C the week of March 8. Vitamin C took a dip in early February and was steadily increasing at the beginning of March.

Vitamin C in tomatoes took a dip in February and steadily increased into March

Which Country of Origin Provided the Most Vitamin C in Bananas?

Bananas are one of the most popular fruits in the U.S., and you probably had one for breakfast or as a snack today. At TeakOrigin, we found that Colombia provided the most vitamin C in bananas. Colombia had almost 11% more vitamin C than its closest competitor (Honduras) and 58% more than Peru.

“This is an example of why we need to start gathering data. We don’t know why Colombia’s bananas have more vitamin C. It may have something to do with their farming or crops. It may also have something to do with their transportation process.” says Overcash. “Our modern food supply chain has created consequences for nutrient levels that we have never looked at before on this scale.”


Did Stores in Los Angeles Provide More Vitamin C Than Stores in Boston?

The answer is that it varied by food, but Boston was slightly better overall.

The foods that did better in Los Angeles stores were tomatoes and blueberries. Tomatoes had 23% more vitamin C, while blueberries had 7% more.

However, spinach, bananas, apples, and strawberries contained more vitamin C in Boston stores. Spinach had 27% more vitamin C, apples had 14% more, bananas had 28% more, and strawberries had 7% more.

We can’t confirm the “why” for these results, but it raises important questions about our supply chain.

Vitamin C in foods from Los Angeles (orange) and Boston (green)

Do Regional Stores Provide More Vitamin C Than National Stores?

We only saw a slight difference in vitamin C between regional (local) and non-regional (large national) stores, delivering average vitamin C scores within a percentage point of each other. Regional stores provided an average vitamin C score of 86.5%, while national stores provided an average score of 85.6% in both Boston and Los Angeles.

“Everyone wants to hate on the big national brands, but our data showed they do a good job of giving you quality produce. Walmart outperformed premium regional brands and had the second-highest vitamin C levels,” says Overcash.

Vitamin C Scores by Store in both LA and Boston show consistency

TeakOrigin is enabling the world to ask questions about our food and food system that we could have never asked or tried to answer before. These questions about vitamin C are only a snippet of our data and the potential answers it can reveal about what we eat every day.

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