PQQ (Pyrroloquinoline quinone) may be the first new vitamin to be identified in over five decades. While the compound was first identified in 1979, its presence and function in animals has only started to be understood in the last decade. It’s been found to have antioxidant and neuroprotective properties as well as contributing to mitochondrial health. It is thought to work as as enzyme cofactor somewhat like vitamin B3 (niacin) and vitamin B2 (riboflavin) and so someday may be grouped as one of the B vitamins which, like PQQ, are also water-soluble nutrients.
PQQ was discovered in 1979 from a bacterium, and afterward it was reported to be in common foods. Because PQQ-deprived mice showed several abnormalities, such as poor development and breakable skin, PQQ has been considered as a candidate for vitamin. It was a mystery, however, with what enzyme PQQ is connected, preventing PQQ from being recognized as a vitamin. In this study, we discovered a mammalian PQQ-linked enzyme. The enzyme was involved in the degradation of the amino acid lysine, and it required PQQ to function normally. This brand-new vitamin will be also important for humans, and we are hoping for a great contribution in medical fields.
PQQ’s Effects on Mitochondria
Recent research suggests it helps mitochondria function better (somewhat like the antioxidant and coenzyme CoQ10) and to form new mitochrondia. The mitochondria are chemical energy factories in cells. Human cells can have from a few to hundreds per cell. Aging humans suffer from damage to their mitochondria and declining numbers of mitochondria. Mitochondrial damage and depopulation is thought to be a major factor in some diseases, particularly those involving energy-intensive organs like the brain, heart, and liver. PQQ appears to both help mitochondria avoid oxidative damage and to help form new mitochondria.
Research reported in 2006 shows that PQQ-deficient mice suffer a reduction in the number of mitochondria in their liver cells:
When pyrroloquinoline quinone (PQQ) is added to an amino acid-based, but otherwise nutritionally complete basal diet, it improves growth-related variables in young mice. We examined PQQ and mitochondrial function based on observations that PQQ deficiency results in elevated plasma glucose concentrations in young mice, and PQQ addition stimulates mitochondrial complex 1 activity in vitro. PQQ-deficient weanling mice had a 20–30% reduction in the relative amount of mitochondria in liver; lower respiratory control ratios, and lower respiratory quotients than PQQ-supplemented mice (2 mg PQQ/kg diet).
PQQ’s Effects on Brain Function
Research published in 2007 shows that PQQ works together with CoQ10, another nutrient critical for mitochondrial function, to improve learning ability in rats and helped counter the effects of hyperoxia (elevated blood oxygen) that impairs brain function and memory by causing oxidative damage to neurons. Damage to neurons from oxidation is suspected to be involved in neurodegenerative conditions including Alzheimer’s disease and Parkinson’s disease.
PQQ supplementation appears to help form new memories in rats learning mazes.
CoQ10 did not improve the learning function of the rats, so that no synergistic efficacy was observed by the concurrent supplementation of PQQ and CoQ10. At the late stage of the trials, the rats fed a PQQ-, CoQ10- and (PQQ + CoQ10)-supplemented diets showed higher learning rates than the control rats. However, the efficacies of the supplementations showed no significant difference. From these results, PQQ is likely more effective in improving the learning ability of the rats using space cognition than CoQ10 itself.
It also appears that PQQ helps retain memories despite oxidative stress on the rats.
After the rats learned the location of the platform in the pool, the effect of hyperoxia as oxidative stress on memory function was assessed. When the rats were subjected to hyperoxia as oxidative stress for 48 h, they retained their memories within four days after the oxidative stress treatment. However, their memories suddenly declined five days after the oxidative stress treatment, as previously reported . The rats fed either the PQQ- or CoQ10-supplemented diet showed memory retention even after the oxidative stress treatment for 48 h. Furthermore, the rats fed the concurrent diet of PQQ and CoQ10 showed marked the memory retention (Fig. 2).
PQQ In Diet
PQQ in the diet is not yet well understood. Some are characterizing it as similar to B family nutrients like biotin and folic acid in its presence in food. But PQQ easily transforms into other related compounds that may obscure the total amount of PQQ consumed, so some estimates are that the typical human PQQ consumption per day without supplements might be as high as 1 to 2 milligrams. It is believed to be well-absorbed (around 85% absorption) and not toxic in dosages of less than 60mg per day in humans based upon testing that included complete blood chemistry, liver, and kidney function tests. Some mice and rat studies suggest that the toxicity doesn’t become apparent except with daily dosages of beyond 250mg per kg of body mass.
Some foods that appear to be high in PQQ, along with approximate concentrations in nanograms of PQQ per gram of food, include:
Natto (fermented soybeans) – 61
Parsley – 34
Green tea – 30
Oolong tea – 28
Green pepper – 28
Papaya – 27
Kiwi fruit – 27
Tofu – 24
Spinach – 22
Broad bean – 18
Potato – 17
Carrot – 17
Miso (fermented soybeans) – 17
Cabbage – 16
Banana – 13
Soybean – 9
Tomato – 9
Egg (yolk) – 7
Orange – 7
Celery – 6
Apple – 6
Egg (white) – 4
Milk – 3
It’s clear that many of the best sources of PQQ are not commonly consumed foods in most Western nations. The Japanese diet tends to include a number of foods high in PQQ, including natto, green tea, tofu, miso, and soybeans.
Of common Western foods, parsley, green peppers, and spinach are among the better sources. A little research suggests that a typical bunch of parsley weighs about 60 grams and contains about 2mg of PQQ. A whole green pepper weights about 200 grams and contains about 6mg of PQQ. A bunch of spinach typically weighs about 450 grams and contains about 10mg of PQQ. These foods have nutritional value beyond their PQQ, too, so if you like salads then consider putting in some parsley, green peppers, and spinach to help boost your intake of PQQ and other nutrients without adding much in the way of calories to your meal. I’d suggest eating them fresh as it is possible (though I’m not sure yet) that cooking will degrade the PQQ.
Where to Find More PQQ Information
The article Potential Physiological Importance of Pyrroloquinoline Quinone (PQQ) has a reasonably complete summary of recent research on PQQ, including summaries of dosage and toxicity studies in humans and animals. If you’re interested in learning more about this nutrient and are comfortable reading scientific papers then this is a good place to start.
It is still difficult to find supplements with PQQ in them, especially outside of Japan. Life Extension has recently introduced three new product formulations with PQQ:
Each contains 10mg of PQQ per dose. That’s well above the amount most people get in their diet, but not so high as to be a danger according to toxicity studies on PQQ.
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