Do Tomatoes Prevent Strokes?


| 5 Comments
It seems as though every week there's a new magical property of some fruit or vegetable that promises to cure every ailment under the sun. In October, BBC News published an article that called tomatoes "stroke preventers". But how much merit do these findings have? Is there causation, or just correlation? Will eating tomatoes now help us all prevent strokes in later life?
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The observational study cited in the BBC article was conducted in Finland and was published in Neurology (you can read the abstract here) in October 2012. The participants consisted of 1,031 middle-aged men with no history of stroke. Researchers initially measured carotenoid levels as well as LDL, HDL, blood pressure, body-mass index (BMI) and blood pressure. They also assessed various risk factors such as smoking, diabetes and alcohol consumption. The researchers found that while some carotenoids such as retinol, a-carotene, and β-carotene are not associated with a decreased risk of stroke, lycopene is. Lycopene is a carotenoid high in antioxidants that, according to the Mayo Clinic, "reduced incidence of cancer, cardiovascular disease, and macular degeneration". Lycopene is what gives tomatoes their bright-red color and can also be found in other fruits and vegetables including red carrots, watermelons and papayas.
The men were split into four groups based on their blood carotenoid levels. At the conclusion of the experiment, 67 men had suffered a stroke. Out of the 258 men in the low-lycopene group, 25 had suffered a stroke compared to 11 strokes in the 259 men with high-lycopene levels. On a 95%-confidence interval, the p-value was 0.036, leading to the conclusion that "the risk of stroke was cut by 55% by having a diet rich in lycopene". The low p-value and length of time this study (men were followed for an average of 12.1 years) certainly support the idea that lycopene reduces a middle-aged male's risk of stroke.
Though the sample size of this study seemed appropriate, I question the validity of the conclusion based on the statistics. Out of over 1,000 men, only 67 strokes occurred. In a way, this decreased the sample size to 67, causing one more or one less stroke in the high- or low-lycopene group to make all the difference. I wonder if comparing lycopene levels in men who've had a stroke to those of men with the same age/risk who have not suffered a stroke would yield more conclusive results. Based on the article and this blog, do you think the results of this study have established a correlation between blood lycopene levels and stroke risk? Do you think consuming more tomatoes is a reasonable action for someone who is at high risk/has suffered a stroke? Or should more resources be allocated to perform more studies need to be done on the subject?

5 Comments

While I believe that more studies definitely need to be done before tomatoes can be considered some sort of miracle cure, there is a strong correlation. I think that it would be perfectly reasonable to add tomatoes to your diet even if there is only a chance that eating tomatoes could help prevent strokes. What is eating a tomato compared to having to go through a stroke? This study is far from conclusive though. Would eating tomatoes help prevent strokes in women? I did some research and I could't find any record of studies being conducted on women. I do feel like there is a possibility that tomatoes could be beneficial, but as with many other things, I think more studies need to be done. Who knows what a study would find if it was conducted on a different selection of males or if a study was conducted on women?

Eating healthy on a whole suggests a longer, better life, well according to Science Daily. A study of 2500 adults from age 70-79 was done, and the results suggest that their diets had severely impacted their mortality rate. The rate of mortality increased by 40% for of those who ate high-fat foods than those who ate a range of low-fat foods. The study says that by 2030, 900 million adults will live to age 65 or older. Healthy living not only yields to a longer life, but a functional long life as well. iBenefits, would agree with your results of this post, but not just by eating tomatoes. Healthy eating helps your immune system, as well as energizes the body, and the flow of everything throughout the body. I think that eating right just gives your body what it needs to go on it's merry functional way, and it does not hinder it's progress.

The entire time I was reading this post, I couldn't help but keep thinking to myself, where are all the women? Daniel picked up on this as well in his comment. I think for any study to be attributed to a correlation or causation versus mere chance, it needs to begin with a diversified random sample. This means that the participants in the study need to be both men and women of all different races, ages, and backgrounds. Based on this information, the results of this tomato study can be considered when you're deciding between tomatoes and carrots- but I wouldn't dramatically change my diet or what I eat to accommodate this so called "stroke-preventer".

The entire time I was reading this post, I couldn't help but keep thinking to myself, where are all the women? Daniel picked up on this as well in his comment. I think for any study to be attributed to a correlation or causation versus mere chance, it needs to begin with a diversified random sample. This means that the participants in the study need to be both men and women of all different races, ages, and backgrounds. Based on this information, the results of this tomato study can be considered when you're deciding between tomatoes and carrots- but I wouldn't dramatically change my diet or what I eat to accommodate this so called "stroke-preventer".

If you take a look at this site it may help you gain a better understanding of factors that increase risk of stroke as well as risk factors that can be changed and not changed. Many of the the risk factors that cannot be controlled were kept constant in the participants. For example, men are more likely to suffer a stroke than women (all participants were men), prior strokes increase the risk of having another stroke (all of the men had no history of stroke), risk increases with age (participants were between the ages of 46-65) and African Americans have a higher risk than Caucasians (the men in the study were all Finnish). Some risk factors that can be controlled or treated include: high blood pressure, smoking, diabetes, physical inactivity, cholesterol, and diet. All of these factors were measured and recorded prior to the start of the experiment. However, here lies a fatal flaw. As I mentioned, the men were followed for an average of 12.1 years. However, it is not mentioned whether or not these factors were reexamined at the end of the experiment. It is very possible that factors such as physical activity and smoking could have changed over the 12 years, thereby increasing/decreasing risk.

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