Phosphate is a charged particle (ion) containing phosphorus, a mineral found in our food. In the body, most phosphorus combines with oxygen to form phosphate, about 85% of which is found in bones. Phosphate plays a number of important roles, from building bones and teeth to serving as a component of compounds used in cellular energy, cell membranes, and DNA.1
However, when eating a typical Western diet high in processed foods, meats, and grains, it is very easy to overdose on phosphorus. This can be detrimental to your health, especially if your calcium levels are low.
High phosphate intake may affect mitochondrial function and promote oxidative stress.
Studies have shown that high intake of bioavailable phosphate can affect mitochondrial function, leading to oxidative stress and vascular calcification.2 What’s interesting is that maintaining adequate magnesium levels may help protect against these harmful effects.
In the body, phosphate can act on the mitochondria, the power plants of cells, to increase the cell membrane potential. This increased cell membrane potential increases the production of superoxide, a type of reactive oxygen species (ROS) that causes oxidative stress in the body.
Increased oxidative stress due to high phosphate levels can lead to vascular calcification. In chronic kidney disease (CKD), high phosphate levels promote the transition of vascular smooth muscle cells to a bone-like state, contributing to vascular stiffness.3
The hormone fibroblast growth factor 23 (FGF23), which increases in response to high phosphate levels, also contributes to oxidative stress and vascular damage. FGF23 further promotes these detrimental effects by activating specific pathways in heart cells and blood vessel lining.
Having adequate levels of magnesium in your body can help counteract the harmful effects of high phosphate levels.4 Magnesium may reduce oxidative stress and prevent vascular calcification by alleviating the increase in mitochondrial membrane potential caused by phosphate.
Studies have shown that magnesium in the diet has a protective effect against these problems, suggesting that maintaining adequate magnesium levels may act as an antidote to the negative effects of high phosphate intake.
The proposed mechanism involves the ability of magnesium to counteract the effects of phosphate on mitochondrial membrane potential.5 This interaction may explain why magnesium is beneficial in preventing vascular calcification. Furthermore, it suggests that magnesium may have a broader protective effect against the harmful effects of high blood phosphate levels, known as hyperphosphatemia.
Your dietary calcium to phosphate ratio is important for metabolic health
The calcium to phosphate (Ca:P) ratio in your diet is important for optimal metabolic health. Calcium is the most abundant mineral in your body, and phosphorus is the second.6 However, the body cannot make this essential mineral. Almost all calcium (99%) is found in teeth and bones. The rest is found in nerve cells, body tissues, blood, and other body fluids.
Because calcium is so important for proper functioning, the body strictly regulates the amount of calcium in the blood to a relatively narrow level of 8.5 to 10.5 mg per dl of extracellular fluid.7 For optimal health, calcium needs to be kept in the bones. If calcium is stored in soft tissue instead, health problems can occur.
Unfortunately, dietary calcium has recently gotten a bad rap, mainly due to fears of calcification, or calcium deposits in body tissues. These deposits can form hard deposits in soft tissues, arteries, and other areas, and can interfere with organ function, such as hardening of the blood vessels of the heart.
However, dietary calcium is not the cause of this calcification. Low dietary calcium is. According to Dr. Ray Pitt:
“It is very important to realize that calcium deposition in soft tissues is aggravated by a diet that is deficient in calcium… Eating a diet that is deficient in calcium is counterproductive because it increases intracellular calcium at the expense of bone calcium.
… There are many such paradoxes. When bones lose calcium, soft tissues become calcified. When calcium intake is reduced, blood calcium can increase, and calcium in many organs and tissues also increases. When organs such as the heart are deprived of calcium for a short period of time, their cells lose the ability to respond normally to calcium and instead absorb large amounts of calcium, which is highly toxic.”
In fact, dietary calcium deficiency is a major problem worldwide, leading to bone problems, increased parathyroid hormone (PTH) levels, and increased soft tissue calcification. When dietary calcium is insufficient, the body compensates to maintain blood calcium levels within the desired range.
If dietary calcium intake is insufficient to meet the body's calcium needs, the parathyroid glands almost immediately release PTH into the bloodstream to restore calcium levels to normal. According to the Journal of the American College of Nutrition, “When calcium intake is low, … parathyroid hormone (PTH) increases, which in turn increases calcium influx into vascular smooth muscle cells.”8
The ideal calcium to phosphorus ratio is close to or greater than 1:1.
The ideal Ca:P ratio is 1:1 to 1.3:1.9,10,11 However, in many countries, phosphate intake is two to three times higher than recommended levels.12,13 While total dietary calcium remains below the recommended level,14 This results in a lower Ca:P ratio.15 However, when calcium levels are low, PTH is secreted, which triggers a stress response in the body, signaling that it is not getting enough calcium.
PTH signals body tissues to convert the stored form of vitamin D to 1,25 D (also called calcitriol or activated vitamin D). 1,25 D provides a signal to pull calcium from the bones and into the bloodstream.
Calcium is not the only nutrient that is effective in suppressing anti-metabolic PTH. You also need adequate levels of magnesium and vitamin D. All of these work together to regulate PTH levels. And as Nursing Times notes, phosphate homeostasis is equally complex.16
“There is some variation in normal plasma phosphate levels quoted in the literature, but values of 0.70-1.50 mmol/L are typical of the quoted values… Regulation of phosphate homeostasis is complex, primarily involving PTH, fibroblast growth factor 23 (FGF23), and vitamin D.
In addition to its role in calcium homeostasis, PTH increases the release of phosphate from mineral stores in bone and simultaneously enhances phosphate elimination in the urine.
Likewise, FGF23 enhances renal phosphate clearance. PTH and FGF23 together decrease plasma phosphate concentrations. Conversely, vitamin D antagonizes PTH and FGF23, enhancing intestinal phosphate absorption and thus increasing plasma phosphate concentrations.”
Too much phosphate can harm your heart and promote aging.
Maintaining the proper balance of phosphate is essential for life, so we have developed a complex system to regulate phosphate levels. However, because the kidneys are responsible for removing phosphate, people with impaired kidney function often have too much phosphate in their bodies.
Too much phosphate is known to cause bone and mineral problems in patients with chronic kidney disease. Recent studies have also shown that high phosphate levels can harm the heart and accelerate aging.17 In fact, phosphate toxicity is one of the reasons why chronic kidney disease promotes premature aging.18 Elevated FGF23 and PTH levels are associated with these negative health effects.
It is common practice to manage phosphate levels in patients with advanced chronic kidney disease. However, because too much phosphate can be toxic to humans, the researchers wrote in Kidney International, “The general population may also benefit from phosphate management.”19 Pete commented:
“Recent publications have shown that too much phosphate can increase inflammation, tissue atrophy, vascular calcification, cancer, dementia, and the aging process in general… Maintaining a high calcium-to-phosphate ratio helps combat stress metabolism.”
How to improve the Ca:P ratio
Fast food and processed food products are major contributors to the increase in dietary phosphate consumption. Phosphates are widely used as preservatives and flavor enhancers in processed foods. Estimated daily intake of food additives containing phosphate has more than doubled since the 1990s.20
On food labels, phosphates may be listed under a variety of names, including sodium phosphate, calcium phosphate, monopotassium phosphate, and pyrophosphate. They are commonly found in frozen pizza, soda, processed cheese, processed meats, and many other ultra-processed foods. Phosphates are also found in meats, seeds, beans, nuts, and whole grains.
I disagree, but DiNicolantonio recommends a plant-based diet to regulate dietary phosphate absorption, optimizing magnesium, vitamins K and D, and other strategies.21
“Dietary phosphate absorption can be modulated by emphasizing plant-based dietary choices (which provide phosphate in less bioavailable forms), avoiding processed foods with inorganic phosphate food additives, and taking phosphate binder drugs, magnesium supplements, or niacin, which precipitate phosphate or inhibit its gastrointestinal absorption.
The tendency of dietary phosphate to promote vascular calcification may be counteracted by optimal intake of magnesium, vitamin K, and vitamin D. The latter should also counteract the tendency of phosphate to increase parathyroid hormone.”
As I said before, I do not recommend a vegan or vegetarian diet, but I do suggest dietary adjustments that will help restore a balanced Ca:P ratio. In addition to avoiding ultra-processed foods, meat is a phosphorus-rich food, so it needs to be balanced with optimal levels of dietary calcium. The best sources of dietary calcium are:
milk | Cottage cheese | Greek Yogurt |
cheese | Cooked collard greens | eggshell |
Eggshells are made almost entirely of calcium carbonate, which is what makes up nails, teeth, and bones. The calcium in this whole food source is balanced with 27 other minerals, making it easier for the body to absorb and assimilate the nutrients in the shell.
Eggshells have the lowest levels of toxic heavy metals compared to bone meal.22 Bones, especially those of older cattle, can contain high levels of toxic heavy metals such as lead and mercury.
If you don't consume a lot of dairy products, a good place to start is to add about 800 to 1,000 mg of calcium to your diet by taking 1/4 teaspoon three times a day with meals. If you have constipation, supplement with magnesium at the same time.
You can use a food tracking app like Cronometer to figure out your total phosphorus and calcium intake. Divide your total calcium intake by your total phosphorus intake to get your calcium to phosphorus ratio. Again, the ideal ratio is close to 1:1 or slightly higher.
