ISLAMABAD, MARCH 06 (ONLINE): Researchers estimate that more than 1 billion people globally have obesity.
Obesity can increase a person’s risk for several health problems, including joint conditions, such as osteoarthritis.
Scientists from Imperial College London in the United Kingdom and the University of Copenhagen in Denmark have recently found that high levels of caffeine in the blood over a long time, influenced by consumption and genetically controlled metabolism, may help protect the body against both obesity and joint disease.
According to the latest research, more than 1 billion peopleTrusted Source around the world — both adults and children — have obesity.
Obesity can increase a person’s risk for several health problems, including joint conditions such as osteoarthritisTrusted Source. This is because when a person carries too much weight, it puts additional strain on the kneesTrusted Source, hipsTrusted Source, and anklesTrusted Source.
Now, researchers from Imperial College London in the United Kingdom and from the University of Copenhagen in Denmark have found that higher levels of caffeine in the blood over a long period may help protect the body against both obesity and joint disease.
The study recently appeared in the journal BMC MedicineTrusted Source.
Why study caffeine in relation to obesity, joint health?
Dr. Dipender Gill, a clinician scientist at Imperial College London and lead author of this study, told Medical News Today they decided to study the effect of caffeine on obesity and joint health because caffeine is widely consumed, and they believe it important to better understand its broad effects on health.
For this study, Dr. Gill and his team focused on circulating caffeineTrusted Source in the body.
“This is the amount of caffeine circulating in the blood and is thus pharmacologically active to affect bodily functions,” he explained.
Additionally, the researchers looked at genetic variants related to caffeine metabolism and how that may affect and break down circulating caffeine levels in the blood, also known as plasma caffeine.
“The use of large-scale human genetic data enabled us to provide rapid and cost-effective clinically relevant insight into the effects of plasma caffeine on a broad range of traits and diagnoses,” Dr. Loukas Zagkos, honorary research associate in molecular epidemiology at the Imperial College London and co-first author of this study told MNT.
Genetic data confirm potential protective effect of caffeine
For this study, Dr. Gill and his team first created a weighted genetic risk scoreTrusted Source (GRS) for plasma caffeine using two genetic variants independently associated with plasma caffeine levels.
The GRS was then used to conduct a phenome-wide association studyTrusted Source (PheWAS) featuring 988 clinical traits recorded in the U.K. Biobank related to circulating caffeine levels.
From there, the researchers used a Mendelian randomizationTrusted Source analysis to figure out the potential mechanisms underlying the effects of plasma caffeine on previously reported and novel traits.
Scientists also obtained genetic data for plasma caffeine from previous genome-wide association studiesTrusted Source (GWAS) of about 9,900 people, mainly Europeans between the ages of 47 and 71. They also received genetic information for osteoarthrosis and osteoarthritis, as well as body mass index details.
Dr. Héléne Toinét Cronjé, a researcher at the University of Copenhagen and co-first author of this study explained to MNT:
“I think the most important aspect of this work is that it allowed us to reframe some of the previous observational findings around caffeine and health outcomes by investigating blood levels of caffeine as opposed to caffeine consumption behavior and doing so through the Mendelian randomization method which uses randomly allocated genetic variation to investigate the causal relationship between an exposure and outcome.”
“This allowed us to circumvent many of the confounding factors that limit observational research such as not knowing whether the effect is specific to caffeine or represents other compounds included in caffeinated products consumed,” Dr. Toinét Cronjé added.
Lower obesity, joint disease risk linked to higher blood caffeine
At the conclusion of the study, the researchers found that long-term increases in circulating caffeine may help lower body weight and a person’s risk of osteoarthrosis and osteoarthritis.
They also confirmed prior genetic evidence of a protective effect of plasma caffeine on a person’s obesity risk.
“We have previously performed such analyses to find evidence supporting [the] effects of plasma caffeine on reducing obesity,” Dr. Gill said. “The current work reinforced these findings and further extended to potential beneficial effects on risk of osteoarthritis.”
“In this study, we report an association between higher genetically predicted plasma caffeine levels and a lower risk of osteoarthritis,” Dr. Zagkos added.
“Around a third of the protective effect of plasma caffeine on osteoarthritis risk was mediated through lower body weight. We replicated prior findings suggesting the protective effect of higher plasma caffeine levels on obesity risk. Further clinical [studies] in the form of randomized trials may now be warranted to understand the translational relevance of our findings,” he cautioned.
“Consuming more caffeine differs from having high levels of caffeine — indeed, people who metabolize caffeine faster typically consume more caffeine to have the same level of caffeine in their blood than those with lower metabolic rates who consume less caffeine,” Dr. Toinét Cronjé said.
“Therefore, while prior research has reported that caffeine consumption might be a risk factor for osteoarthritis and obesity, our results clarify that the causal association is between lower caffeine levels across the life course and disease liability and that the behavioral trait of increased caffeine consumption reflects faster caffeine metabolism.”
– Dr. Héléne Toinét Cronjé
How much caffeine is healthy?
MNT also spoke with Dr. Mir Ali, a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, about this study.
Dr. Ali said he was not surprised by its results: “I have seen similar studiesTrusted Source before showing that caffeine is helpful with weight loss, but it was good to have another confirmation of that.”
When asked how much caffeine a person should consume to potentially lower their obesity or joint health risk, Dr. Ali said some studies have shown that 3 milligrams (mg) of caffeineTrusted Source per kilogram (kg) of body weight is sufficient.
“So somebody who’s about 70 [kg] — that’s 154 lbs [pounds] — would need about 210 [mg] of caffeine, which is a little more than 2 cups of coffee,” he detailed. “I’ve seen that range anywhere from 200 to 400 [mg]Trusted Source a day.”
However, Dr. Ali advised it is also crucial to remember that everyone responds to caffeine differently.
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