Turns out Popey was right when it comes to spinach. Spinach DOES help with muscle growth.
Chemicals in spinach help to speed up the body’s conversion of protein into muscle mass, as scientists found out in 2008. They extracted specific chemicals from spinach, called phytoecdysteroids, and placed them on human muscle tissue in a lab. The result? Muscle growth sped up by 20%!
When scientists injected rats with a phytoecdysteroids extract for a month, the rats became stronger and increased their grip strength.
Tim Ferriss has a few things to say about spinach in his book “The 4-Hour Body”.
Betaine is formed from choline within the mitochondria, and this oxidation contributes to mitochondrial redox status.” Guess what another primary source of betaine is? Spinach. This is where credit is due: Popeye got it right. Spinach is incredible for body re-composition.
The phytoecdysteroids (20HE specifically) in spinach increase human muscle tissue growth rates 20% when applied in a culture (think petri dish). Even if you’re not interested in growth, it also increases glucose metabolism. Phytoecdysteroids are structurally similar to insect moulting hormones—finally, an affordable way to eat insect moulting hormones!—and both increase protein synthesis and muscular performance. Even little rats build stronger paw grips. In good news for women, the 20HE ecdysteroid tested demonstrates no androgenic properties. In other words, it won’t give you a hairy chest or an Adam’s apple. The Rutgers University researchers responsible for the principal study emphasize, almost as a deterrent, that one would need to eat 1 kilogram (2.2lb) of spinach per day to mimic the administration used. In testing, I’ve found that it’s not hard at all to see a visible effect with smaller amounts. I routinely eat 162–243g (5.7–8.6oz) of spinach per day, which is less than you think. 162g (5.7oz), is about 16% of 1kg (2.2lb). 243g (8.6oz) is almost 25% of 1kg (2.2lb). If the results of the study are dose-dependent, one might expect an increase in muscle fibre synthesis of 3% from 162g (5.7oz) and 5% from 243g (8.6oz), not to mention the effect of increased carbohydrate metabolism. Compounded over time, this is significant. If the effect is not dose-dependent but rather triggered at a dose less than 1kg (2.2lb) per day, it is possible that the 20% increase could be achieved with far less than 1kg (2.2lb). I also believe that spinach increases cAMP, but that’s for the geeks to explore.
Later in the book he discusses the importance of potassium, magnesium and calcium for muscle gains:
SHOULD I TAKE ANY SUPPLEMENTS?
I suggest potassium, magnesium and calcium. This diet will cause you to lose excess water, and electrolytes can go along with it.[…]
If you prefer to get your electrolytes through whole foods, here are good slow-carb options, in descending order of concentration. Notice that spinach is the only item on all three lists:
According to Ferriss, cooked spinach scores really well on all three nutrients:
Potassium: 1kg (2.2lb) (180g/6.3oz = 839mg)
Calcium: 738g (1.6lb) (180g/6.3oz = 245mg)
Magnesium: Spinach, 450g (1lb) (180g/16.3oz = 157mg)
And there’s a great article on Dr. Jockers on spinach, and how it facilitates muscle growth.