Popeye is right: spinach makes you stronger, study shows

June 25, 2012

Famous cartoon character Popeye is right to down a can of spinach when he wants his biceps to bulge, according to a Swedish study presented Monday showing why the leafy vegetable makes us stronger.

Researchers at the Karolinska Institute in Stockholm said Monday they had conducted a study showing how nitrate, found naturally in spinach and several other vegetables, tones up muscles.

For the study, which will be published in the Journal of Physiology, the research team had placed nitrate directly in the drinking water of a group of mice for one week and then dissected them and compared their functions to that of a control group.

"The mice that had been on consistent nitrate had much stronger muscles," they said in a statement.

The nitrate used "was equivalent to a human's consumption of about 200 to 250 grammes of spinach a day, so it's a very easily obtained amount," one of the researchers at the Department of Physiology and Pharmacology, Andres Hernandez, told AFP.

"Well, it is if you eat spinach. For people who don't eat their vegetables it will be more tricky," he added.

While no effect could be seen in the so-called slow-twitch muscles used for and endurance, the scientists saw a clear change could be seen in the fast-twitch muscles used for strength and more high-intensity exercises, Hernandez said.

The tricky question, he said, was determining why this happened.

The researchers discovered that the nitrates had prompted an increase in two proteins, found naturally in the muscles, that are used for storing and releasing calcium, which is vital to making muscles contract.

The protein increase in turn led to higher quantities of calcium released in the muscles, Hernandez said, pointing out that "if you have more calcium released, you have a stronger contraction."

Translated into human terms, consuming nitrates from for instance increases the available for things like lifting weights or sprinting up a steep hill.

It could also increase endurance, Hernandez said, pointing out that when stronger, the fast-twitch muscles, which fatigue faster than other muscles, do not need to contract as frequently.

This is not only good news for exercise buffs looking to improve their performance.

"The really exciting part is to go ahead and look at people with muscle weakness, with muscle diseases, and even aging, and see if this can actually improve their muscle function," Hernandez said.

He said the research team aimed to conduct a few more studies on mice but hoped to also carry out studies on humans soon.

Explore further: Role of gene regulator in skeletal muscles demonstrated

More information: Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse fast-twitch muscle, Journal of Physiology, Epub ahead of print 11 June 2012, doi:10.1113/jphysiol.2012.232777 . www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=22687611&query_hl=2&itool=pubmed_docsum

Related Stories

Role of gene regulator in skeletal muscles demonstrated

June 2, 2011

Fast muscles, such as the thigh muscle in a sprinter, deliver energy quickly but fatigue quickly. Slow muscles, such as the soleus muscle in the lower calf, are less forceful but important for posture and endurance. Researchers ...

Weakness in aging tied to leaky muscles

August 2, 2011

There is a reason exercise becomes more difficult with age. A report in the August Cell Metabolism, a Cell Press publication, ties the weakness of aging to leaky calcium channels inside muscle cells. But there is some good ...

Targeting leg fatigue in heart failure

October 31, 2011

Doctors should not only treat the heart muscle in chronic heart failure patients, but also their leg muscles through exercise, say researchers in a study published today in the Journal of Applied Physiology.

New clues to muscle wasting in elderly people

February 24, 2012

Permanent disconnection between nerves and muscles may be the reason behind progressive loss of muscle mass and function in elderly people, Perth-based researchers have found.

Recommended for you

New 'Tissue Velcro' could help repair damaged hearts

August 28, 2015

Engineers at the University of Toronto just made assembling functional heart tissue as easy as fastening your shoes. The team has created a biocompatible scaffold that allows sheets of beating heart cells to snap together ...

Fertilization discovery: Do sperm wield tiny harpoons?

August 26, 2015

Could the sperm harpoon the egg to facilitate fertilization? That's the intriguing possibility raised by the University of Virginia School of Medicine's discovery that a protein within the head of the sperm forms spiky filaments, ...

Research identifies protein that regulates body clock

August 26, 2015

New research into circadian rhythms by researchers at the University of Toronto Mississauga shows that the GRK2 protein plays a major role in regulating the body's internal clock and points the way to remedies for jet lag ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Keith12
not rated yet Jun 27, 2012
That's crazy, I guess Popeye had it right.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.