Newsletter #318: Tomato Consumption and Blood Pressure 🫀
High blood pressure is classically referred to as a “silent killer” because it can wreak havoc in the body without showing obvious symptoms. And it is astoundingly common. According to the CDC, nearly half of American adults have hypertension, and risk tends to go up as we get older.
Consequently, there is enormous interest in dietary components that can help keep blood pressure in a healthy range. One that has recently emerged is lycopene, which acts on multiple pathways that influence blood pressure.
From Przybylska & Tokarczyk, 2022.
First of all, lycopene has been shown to inhibit the activity of angiotensin-converting enzyme (ACE). This enzyme is responsible for the production of angiotensin II, which causes blood vessels to constrict, leading to higher blood pressure. ACE inhibitors are a class of commonly prescribed anti-hypertensive drugs, and lycopene appears to share the mechanism of action exerted by these medications (albeit less potently, I would presume).
Lycopene also lowers blood pressure indirectly through its antioxidant effects. Reactive oxygen species interfere with the generation of nitric oxide in the walls of the blood vessels. By triggering natural antioxidant defenses, lycopene has been shown to enhance nitric oxide, causing blood vessels to widen.
One recent meta-analysis found that supplementation with lycopene reduced systolic blood pressure by an average of 5.66 mmHg, and improved flow-mediated dilation by 2.53% (FMD is basically a measurement of the capacity of an artery to widen in response to increased blood flow).
The best source of lycopene in the diet, of course, is tomatoes. But does eating tomatoes have the same beneficial impact on vascular health as supplementing with lycopene pills? Recently, researchers in Spain published the first large longitudinal study to explore the association between tomato and tomato-based products and hypertension. Let’s take a look at what they found.
This Week’s Research Highlight
🍅 Tomato consumption is associated with lower blood pressure and reduced risk of hypertension.
To assess whether eating tomatoes influences blood pressure regulation, Spanish researchers took advantage of a treasure trove of data gleaned from the PREDIMED study. PREDIMED is a large randomized trial enrolling more than 7,000 older people who are deemed to be at high cardiovascular risk. These people are being monitored by health researchers to see how manipulating aspects of their diet affects their health outcomes over time. And since they live in the Mediterranean region, where tomatoes are prominently featured in the diet, this is a good population to look at for the purposes of this study.
The research team analyzed dietary assessments which had been administered by trained dietitians at three different intervals, ultimately following the subjects for three years.
They classified the subjects into quartiles based on their average daily tomato intake.
- lowest (<44 g per day)
- intermediate (44–82 g per day)
- upper-intermediate (82–110 g per day)
- highest (>110 g per day)
Then, they compared the blood pressure levels and hypertension incidence in these groups.
The researchers found that individuals with the highest tomato consumption pattern (a mean of more than 110 g/day, about one tomato) had a 36% reduced risk of hypertension.
When they compared blood pressure across all groups, a linear trend emerged for decreasing systolic and diastolic BP with increasing tomato consumption — in other words, being in the intermediate category of consumption was linked to lower BP than the lowest, and the upper intermediate category had lower BP than the intermediate, and so on. So generally speaking, more tomatoes is better.
However, this effect was only significant in participants with grade 1 hypertension. People with more severe hypertension (systolic BP above 140 mm Hg) did not see the same benefits. That’s not super surprising, especially in an elderly population like this one. Very high blood pressure, over time, leads to harmful adaptations in the cardiovascular and renal system, and is usually accompanied by multiple comorbidities. It’s a more complicated problem. Furthermore, aging itself may adversely affect the bioavailability and metabolism of carotenoids like lycopene, meaning these folks may simply be less responsive to them.
Regardless, for people with grade 1 hypertension, we know that relatively modest reductions in blood pressure, elicited through diet modification, can make a big difference in long-term outcomes. A 10 mmHg reduction in systolic blood pressure has been shown to reduce cardiovascular disease risk by 20%, coronary heart disease by 17%, stroke by 27%, heart failure by 28%, and all-cause mortality by 13%. Fortunately, consuming tomatoes, as opposed to supplementation, seems to be an effective strategy for achieving these benefits, based on the findings of this study.
Finally, another interesting aspect of lycopene is that it accumulates in tissues within the body, and it has a very long half-life in plasma, as long as 12-33 days. This suggests that it could exert beneficial effects even if consumed intermittently (in other words, you wouldn't necessarily need to make sure you're eating it every day to reap the benefits).
Random Trivia & Weird News
🏃♂️ A Japanese juice company made a wearable robot that feeds people tomatoes while they run.
A while back, Japanese juice maker Kagome revealed a device dubbed “Tomatan,” which they cleverly showcased during a 5K run.
Tomatan is basically a humanoid backpack that can be loaded with tomatoes. When the wearer tugs a lever under the foot of the Tomatan, the arms of the device rotate a tomato in front of the user’s mouth, enabling them to eat the tomato hands-free as they run.
Why tomatoes specifically? According to a representative from the company, “Tomatoes have lots of nutrition that combats fatigue.”
Podcasts We Loved This Week
- Jordan Feigenbaum: Strength and fitness levels for reducing chronic disease risk and promoting healthy aging. Via Sigma Nutrition Radio.
- John Kounios: Creative flow — what’s going on inside the brain when everything just clicks. Via The Conversation Weekly.
Products We Like
Double Concentrated Tomato Paste
Tomatoes are an interesting illustration of how processing can, in some cases, enhance the health-promoting properties of specific foods.
We’ve known for a long time that tomato paste is a far better source of lycopene than fresh tomatoes. Carotenoids, such as lycopene, are tightly locked up with proteins in the plant matrix, and as a result the human digestive tract has a tough time capturing these phytochemicals from whole tomatoes. However, when you chop up or cook tomatoes, like when making tomato sauce or paste, that plant matrix is disrupted, releasing loads of carotenoids.
But tomato paste usually comes in six ounce cans, which isn’t super practical. That’s why these resealable tubes are so handy. You can use just a little bit and then store them in the fridge for whenever you need it. Plus they are double concentrated, so you get an extra large dose of tomato flavor and lycopene per serving.
humanOS Catalog Feature of the Week
The How-to Guide to the Mediterranean Diet
In this reference sheet, we go over the fundamental principles of the Mediterranean diet, what components of the diet make it healthy, and what sorts of foods and beverages you should consume in order to achieve the best possible version of this dietary pattern based on the current scientific literature. And obviously, tomatoes and tomato products are a hallmark of the Mediterranean diet.
For a little bit of a deeper dive, you can refer to our Mediterranean Program, which delves into the background of the Mediterranean diet as well as the clinical research.
Wishing you the best,
