Spicy Foods May Boost Lifespan – But Only for Non-Drinkers
If you have been watching the news lately you’ve probably seen or heard the story: A new study showing that eating spicy foods regularly may increase lifespan as much as 14 percent.
But you may not have heard the rest of the story.
Most people figure – ‘heck, let’s just add more spicy foods to our currently unhealthy lifestyle and we’ll live longer.’ But there is a caveat: The benefits of a spicy diet are only associated with those who do not regularly drink alcohol.
Before we discuss this caveat, let’s first cover the primary details of the study.
Large study shows spicy foods may increase lifespan
The study was conducted by a consortium of researchers from the Harvard School of Public Health and the Harvard Medical School along with the Chinese Academy of Medical Sciences, Peking’s School of Public Health at the Peking University Health Science Center and the UK’s University of Oxford. The researchers conducted a population study of 10 regions of China. The total number of people in this epidemiological study was 487,375. They were each between the age of 30 and 79 years old.
The population was followed for an average of a little over seven years. During that time, 20,224 people died. The researchers tracked their diets with survey questions, such as:
“During the past month, about how often did you eat hot spicy foods?”: never or almost never, only occasionally, 1 or 2 days a week, 3 to 5 days a week, or 6 or 7 days a week?”
They also asked what kinds of foods provided the spice, and a number of other dietary and health questions, including how much alcohol they drank and how much red meat they ate – because these two factors have been shown to decrease lifespan. In addition, they questioned the subjects on how much healthier foods they ate such as fruits and vegetables. In addition, they measured body weight, BMI, blood pressure and plasma glucose levels – and assessed their medical history for conditions known to shorten lifespan.
In addition the researchers also measured other factors such as household income and occupation to test other lifestyle factors.
The researchers also randomly selected a group of 1,300 people from the population to be questioned and tested more frequently. This allowed the researchers to test and confirm the larger results of the study.
Spicey meals lead to lower death rates
Most of the media reported on the central results of the study. That is, those men and women who ate a spicy meal one to two times per week had a 10 percent decreased incidence of death within the seven-year followup period.
And those who ate a spicy meal more than two to three times per week had a 14 percent decreased incidence of death during the seven year period.
This essentially equates to – in epidemiological terms – the possibility of living 10 percent to 14 percent longer. Though this is not necessarily a straight-line assumption, one could generally take away that conclusion.
This general decreased incidence of death was also found among diseases such as cancer, heart disease and others. These conditions were all in the range of 10-14 percent less for those who ate spicy foods nearly every day.
The big alcohol caveat beneath the headlines
As mentioned above, most of the media coverage I read on this study did not cover a critical caveat of the research: That the association between spicy foods and mortality was only significant among those who did not drink alcohol regularly.
In studies like this, associations between a lifestyle or dietary preference are rated using a value called the P-value – which basically relates to its probability. When the P-value is high enough, the association is considered significant.
In other words, in a large study like this, the results are confirmed with the P-value to test the probability that a particular activity is indeed associated with the particular outcome.
For those who did not drink alcohol regularly, the probability statistic P-value was good – at P=0.708. However, for those who drank alcohol regularly, the P-value was only 0.033. Not so good. This left the association between spicy foods and decreased mortality for drinkers not significant enough to call it a true association.
The bottom line: The association between decreased mortality and spicy foods was not significant for regular alcohol drinkers. So regular alcohol drinkers should not expect any significant lifespan benefit from eating spicy foods.
We should note that some of the other lifestyle factors, such as being overweight or being a smoker – did not affect the P-value that much. The P-value for smokers was 0.81 and the P-value for those who were overweight was still 0.51. This means that even smokers or those who are overweight will still benefit from eating spicy foods.
As long as they are not regular alcohol drinkers.
Problems associated with drinking
The reasons for this lack of benefit among drinkers was not explained by the study. One might easily conclude that alcohol somehow interferes with the benefits of spicy foods. This may be related to the gut’s probiotics – as spicy foods can benefit our probiotics.
On the contrary, regular alcohol consumption has been shown to decrease our gut’s probiotic health. Research has illustrated that pathogenic bacteria tend to increase in the gut and healthy probiotic bacteria are decreased during regular alcohol consumption.
The alcohol factor in this spicy food study may only be this author’s hypothesis. But the relationships mentioned above are backed up by scientific research (as always, see below for references).
And for those who were happy about early studies showing that regular but minimal alcohol consumption was healthy: Sorry, but this research is outdated: More recent studies have shown that even light regular drinking is deleterious to our health.
Sources of beneficial spicy foods
The researchers also determined how the spicy food eaters were getting their spice. Most of the spicy foods they ate contained either dried red peppers or chopped fresh red peppers, although some also ate other types of peppers were also eaten.
The critical factor here is the constituent called capsaicin – a central component of red peppers. Capsaicin has been shown in other studies – many reported in this publication – to decrease inflammation, help weight loss, help prevent cancer and help reduce heart disease.
Some reports have shown that capsaicin and red peppers in general also support the growth of probiotics within the gut. Whether this comes as a result of peppers being a prebiotic or the fact that peppers are antibacterial against many pathogenic bacteria is not fully proven out. By eliminating these competitors of probiotics, red peppers may simply help probiotics expand their colonies. This is a territorial thing.
Many of these benefits may also be obtained from other types of peppers – notably capsinoids, which are easily broken down in the gut and are less likely to cause stomach upset and exasperate ulcers. These contrast with capsaicinoids such as capsasin from hot, red peppers. Capsinoids are found in red peppers, but they are also found in many mild and green peppers – including sweet red and green peppers.
Lv J, Qi L, Yu C, Yang L, Guo Y, Chen Y, Bian Z, Sun D, Du J, Ge P, Tang Z, Hou W, Li Y, Chen J, Chen Z, Li L; China Kadoorie Biobank collaborative group. Consumption of spicy foods and mortality: population based cohort study. BMJ. 2015 Aug 4;351:h3942. doi: 10.1136/bmj.h3942.
Forouhi NG. Consumption of hot spicy foods and mortality-is chilli good for your health? BMJ. 2015 Aug 4;351:h4141. doi: 10.1136/bmj.h4141.
Malaguarnera G, Giordano M, Nunnari G, Bertino G, Malaguarnera M. Gut microbiota in alcoholic liver disease: pathogenetic role and therapeutic perspectives. World J Gastroenterol. 2014 Nov 28;20(44):16639-48. doi: 10.3748/wjg.v20.i44.16639.
Billing J, Sherman PW. Antimicrobial functions of spices: why some like it hot. Q Rev Biol. 1998 Mar;73(1):3-49.
Luo XJ, Peng J, Li YJ. Recent advances in the study on capsaicinoids and capsinoids. Eur J Pharmacol. 2011 Jan 10;650(1):1-7. doi: 10.1016/j.ejphar.2010.09.074.
Singh S, Jarret R, Russo V, Majetich G, Shimkus J, Bushway R, Perkins B. Determination of capsinoids by HPLC-DAD in capsicum species. J Agric Food Chem. 2009 May 13;57(9):3452-7. doi: 10.1021/jf8040287.