Image by Narupon Promvichai from Pixabay

One of the core naturopathic principles is the concept that “the healing is in the blood.” Driving blood flow to the area of an ailment, be it tissue damage or an infection or chronic inflammation, provides the delivery of oxygen and nutrients, and assists with elimination of metabolic waste.

Nitric oxide is a well known vasodilator, which means it increases blood flow. It seems like this would be a universally good thing, right?

Well… maybe, but not necessarily. It depends.

Nitric Oxide: The Good, The Bad, and the Ugly

Nitric oxide can be produced in the body via the endothelial lining or the neurons. In this case, it plays an adaptive role, in smaller quantities.

Alternatively, it can be induced by components of bacteria or viruses. The nitric oxide itself is toxic to those organisms, and it also triggers release of various inflammatory compounds–but it’s also toxic to our own cells, in these large quantities.

In large quantities, while nitric oxide does drive increased blood flow, it paradoxically blocks mitochondrial respiration, which means the cells are less able to use the freshly delivered oxygen usefully. (On the other hand, small amounts of nitric oxide triggers production of new mitochondria.)

Not only that, but large amounts of nitric oxide, a very unstable molecule, will react with oxygen to become peroxynitrite, one of the strongest oxidative stressors.

Oxidative stressors can cause vascular damage, which may be why elevated nitric oxide causes cardiovascular disease.

As an inflammatory agent and the source of significant oxidative stress, chronically elevated nitric oxide can also promote tumor growth and metastasis.

In other words, like so many other feedback mechanisms in the body, nitric oxide acts hormetically. There can be too much of a good thing.

Carbon Dioxide: The Other Vasodilator

While significant nitric oxide synthesis and release can be triggered in an acute situation (such as an infection, mentioned above), there’s a much more elegant feedback system for vasodilation and constriction already in place.

We all know that we breathe in oxygen, and breathe out carbon dioxide. Freshly oxygenated blood travels from the lungs to the tissues, and as part of mitochondrial (or oxidative) respiration, oxygen is used up and carbon dioxide is generated in the process. After blood drops off its oxygen, it absorbs the CO2. Once back in the lungs, the high oxygen content displaces the CO2 in a process called the Haldane Effect, and the lungs breathe the CO2 out.

Because of all of this, when tissues are deprived of oxygen, they’ll still be high in CO2. The CO2 concentration itself triggers vasodilation, as those tissues are hungry for more oxygen, and they need blood flow to get it. Even hemoglobin changes its affinity for oxygen depending upon the CO2 concentration, a phenomenon known as the Bohr Effect.

This study shows that inhaling CO2 actually reverses hypoxia (oxygen deficiency). This may seem counterintuitive, until you consider that higher CO2 will increase vasodilation, which increases the efficiency of oxygen delivery. (The feedback mechanisms that keep the body in balance are stunning!)

CO2 is part of a standard metabolic panel on blood work. Low levels can therefore indicate inadequate blood flow and oxygenation to the tissues. Deep breathing can help, but if this doesn’t correct it, it can be useful to check lactic acid—this will indicate whether the mitochondria are performing oxidative phosphorylation adequately, or not. It’s one “quick and dirty” way to determine whether there might be any mitochondrial dysfunction. 

Increasing Your CO2: Baking Soda

Baking soda is a great natural cleanser, but it does more than just that.

Baking soda is very alkaline, so it can be a quick rescue for those suffering from acid reflux (though this isn’t treating root cause, so not a long-term solution).

Because of its alkalinity, it also can be useful orally to correct acidity in a hurry. This means that it can increase insulin sensitivity, which requires a more alkaline extracellular environment. An acidic environment is known to impair the immune response, so baking soda therefore increases immune function, also.

Directly relevant to our current discussion, baking soda, or bicarbonate, turns into CO2 in the body. This should mean it would increase blood flow—and indeed, it has been shown to improve exercise performance, though it hasn’t been studied for other conditions like erectile dysfunction or angina that I was able to find.

Interestingly, the fact that baking soda becomes CO2 also means it lowers excessively high nitric oxide levels—which would make sense, as they have similar purposes. We would expect a feedback system to prevent redundancy.

Since nitric oxide raises prostaglandins (the inflammatory compounds blocked by NSAIDs), baking soda also tends to lower prostaglandins (and thus, inflammation) as well.

The Upshot

“The healing is in the blood,” but that doesn’t mean every means by which blood flow might increase is necessarily equal, or that more of it is always better. Drugs that work via nitric oxide, particularly of the class for erectile dysfunction like sildenafil/Viagra, carry primarily cardiovascular side effects. This is also a reason to be cautious of supplements that work via the same mechanism, including arginine and citrulline as individual amino acids. (I would not worry at all about sources of nitrates found naturally in food, though—first of all, low levels of nitric oxide are still beneficial, and second of all, God knew what He was doing. The nitrates added to processed meats, however, are a different story.) 

I don’t see baking soda as a cure-all either, but it’s useful to be aware of it as a tool in the short term. And low CO2 on a metabolic panel, not easily corrected with deep breathing, might be a clue to look deeper.