Evidence Based
0

High Phosphate (Phosphorus): Causes, Effects & Ways to Decrease

Written by Biljana Novkovic, PhD | Last updated:
Puya Yazdi
Medically reviewed by
Puya Yazdi, MD | Written by Biljana Novkovic, PhD | Last updated:

SelfHacked has the strictest sourcing guidelines in the health industry and we almost exclusively link to medically peer-reviewed studies, usually on PubMed. We believe that the most accurate information is found directly in the scientific source.

We are dedicated to providing the most scientifically valid, unbiased, and comprehensive information on any given topic.

Our team comprises of trained MDs, PhDs, pharmacists, qualified scientists, and certified health and wellness specialists.

All of our content is written by scientists and people with a strong science background.

Our science team is put through the strictest vetting process in the health industry and we often reject applicants who have written articles for many of the largest health websites that are deemed trustworthy. Our science team must pass long technical science tests, difficult logical reasoning and reading comprehension tests. They are continually monitored by our internal peer-review process and if we see anyone making material science errors, we don't let them write for us again.

Our goal is to not have a single piece of inaccurate information on this website. If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please leave a comment or contact us at [email protected]

Note that each number in parentheses [1, 2, 3, etc.] is a clickable link to peer-reviewed scientific studies. A plus sign next to the number “[1+, 2+, etc...]” means that the information is found within the full scientific study rather than the abstract.

Phosphorus is the second most abundant mineral in the body, essential for energy, bone, heart, lung, and brain health. Imbalances may disrupt your metabolism and raise your risk of chronic diseases. Diet and income can have a huge impact, affecting the number of dangerous phosphate additives in your grocery basket. Learn more about the causes and effects of high blood phosphate and how to optimize it.

What is Phosphorus?

Phosphorus is the sixth most abundant element in the body after oxygen, hydrogen, carbon, nitrogen, and calcium. It is the second most abundant mineral and makes up about 1% of our body weight [1, 2].

Phosphorus is mainly found as phosphate in the body. The terms phosphate and phosphorus are often used interchangeably, although they don’t have the same meaning [2, 3]. Phosphorus is an atom, while phosphate is made when phosphorus is bound to oxygen (4 oxygen atoms).

85% of phosphorus in the body is stored in the bones. The remaining 15% is scattered in tissues throughout the body [4, 5].

Phosphorus has many important roles [2]:

  • Helps build cells, DNA, and proteins
  • Crucial for strong bones and teeth
  • Vital for energy metabolism, as the “P” of ATP – the “energy currency” of our cells
  • Required for muscle contractions and sending out nerve signals
  • As the most abundant anion (negative ion) in the body, phosphate helps maintain the acid-base balance (pH)

Blood phosphate comprises a very small part of total body phosphate. Nevertheless, it gives a good estimate of phosphate levels in the body [6].

Phosphorus in the Diet: The Role of Processed Food

Phosphorus is naturally ubiquitous in all foods: meat, fish, eggs, dairy, and vegetables. Milk and dairy products are the richest sources of phosphorus [3, 2, 2].

A regular Western diet provides between 1,000 and 2,000 mg/day of phosphorus. The average intake of a U.S. adult is around 1,400 mg/day, double the recommended dietary allowance (RDA) of 700 mg/day [2, 7, 8].

It turns out that the amount of total dietary phosphate is directly influenced by the intake of processed food and beverages. However, this is not due to naturally high phosphorus in these food items. Instead, it’s a result of phosphate salts being used as additives [3].

Manufacturers add phosphates to their products to enhance appearance and shelf life. Phosphorus-based additives are used as pH stabilizers, leavening, and anti-bacterial agents. They account for about 10 – 50% of total daily phosphorus intake in the typical Westernized diet [8, 9].

One study looked into over 2,000 best-selling grocery products in Ohio. 44% of them contained phosphate additives. The additives were particularly common in:

  • Prepared frozen foods (72%)
  • Dry food mixes (70%)
  • Packaged meat (65%)
  • Bread & baked goods (57%)
  • Soups (54%)
  • Yogurt (51%)

People who consume meals comprised mostly of phosphorus-additive-containing foods take in 736 mg more phosphorus per day than people who mostly consume additive-free foods. However, “additive-enhanced” food items cost $2 less per day than additive-free meals [10].

In a study of over 7,800 people, milk and dairy products with phosphate additives greatly increased blood phosphorus levels (0.07 mg/dL for each additional serving). Additive-containing cereal and grain products had a similar effect (0.005 mg/dL increase for each additional serving) [11].

Several studies have associated high phosphorus intake or high blood phosphate levels with increased mortality and chronic diseases, including heart disease and cancer [12].

Bioavailability

Natural or organic sources of phosphorus need to be broken down by digestive enzymes, leading to slower and less efficient absorption in the gut. The absorption ranges from 40 to 70% and is higher from animal sources (up to 70%) than from plants (up to 50%). Phytates greatly lower phosphorus bioavailability. They are found in whole grains and vegetables [13, 14, 7].

In a non-fortified mixed diet, most of the digestible phosphorus comes from proteins, making protein-rich foods the main source of natural phosphorus [15].

Conversely, inorganic phosphates used as additives don’t require enzymatic digestion. They are rapidly absorbed and have high bioavailability (over 80%) [13, 15].

Metabolism

Phosphorus is absorbed in the gut, stored in the bones, and removed by the kidneys.

Phosphate in the bones acts as a buffer that responds to specific imbalances. It moves in and out of bones as needed. Bone breakdown releases phosphorus, raising its blood levels. Increased bone mineralization, on the other hand, attracts phosphorus into the bones and lowers its blood levels [7, 2].

In adults, kidneys will normally get rid of a fairly constant amount of phosphorus (> 90%). But when the supply is low, kidneys can reabsorb phosphate very efficiently, reducing urine levels down to virtually zero. Also, when there’s phosphate overload, healthy kidneys can rid the body of any excess amounts [1, 2].

Apart from the obvious – gut, bones, and kidneys – blood phosphate levels are also controlled by the parathyroid gland. Hormones that affect blood phosphate levels are [2, 1, 16, 12]:

  • Calcitriol, or active vitamin D: promotes phosphorus absorption in the gut and increases blood phosphate levels
  • Parathyroid hormone: increases kidney excretion of phosphate and lowers blood phosphate levels
  • FGF23: increases kidney excretion of phosphate and decreases its gut absorption, reducing blood levels

Other hormones, such as thyroid hormones, insulin, corticosteroids, and calcitonin, have a more modest role in phosphate metabolism [1].

Phosphorus metabolism is tightly bound to that of calcium – both minerals are affected by the same hormones, usually in the opposite direction. In addition, phosphate can bind calcium in the blood, thereby reducing its levels. Our health depends on a delicate balance between these two minerals [2, 3].

Normal Range

You can measure your phosphate levels by doing a simple blood test.

In adults, the normal range is between 2.5 and 4.5 mg/dL (milligrams per deciliter). That equals roughly 0.8 – 1.45 mmol/L (millimoles per liter).

High Phosphorus (Hyperphosphatemia)

High blood phosphate levels are called hyperphosphatemia (“hyper” = high, “phosphatemia” = blood phosphorus).

A result that’s higher than normal, doesn’t necessarily mean that you have a health condition needing treatment. Your doctor will interpret your result, taking into account your medical history, symptoms, and other test results.

Causes shown here are commonly associated with high phosphate levels. Work with your doctor or another health care professional to get an accurate diagnosis.

Causes

These increase blood phosphate levels:

  • Kidney disease/failure – impaired kidney function is the most common cause of high blood phosphate levels [17]
  • Too much vitamin D [18]
  • Overdosing on calcium (milk-alkali syndrome) [19, 20]
  • Increased dietary intake of phosphorus-containing foods (phosphate supplementation, soft drinks, and pre-packaged food) [6, 21]
  • Phosphate-containing laxatives and enemas [22, 23]
  • Prolonged exercise [24, 25, 26, 27]
  • Dehydration [28]
  • Smoking [29, 30]
  • Rapid abnormal destruction of red blood cells (hemolysis) or muscle tissue (rhabdomyolysis), where phosphorus “leaks” from damaged muscles into the blood [5, 1, 31, 32, 33]
  • Low parathyroid hormone levels (hypoparathyroidism) [34]
  • Overactive thyroid gland (hyperthyroidism) [35]
  • Diabetic ketoacidosis, a serious life-threatening complication of diabetes in which the body produces too many ketones [36]
  • Acromegaly, caused by too much growth hormone [37]
  • Cancer and initiation of cancer treatment (tumor lysis syndrome) [38, 5]

The following can interfere with phosphate measurement, resulting in falsely high levels:

High Blood Phosphate and Poverty

Two studies have linked high blood phosphate with poverty.

In the first study of 14,000 US adults, participants with income below the poverty level were twice as likely to have high blood phosphate levels (≥ 4.4 mg/dL) [41].

Similarly, in the second study with over 2,800 people, those who had the lowest income or were unemployed were more than twice as likely to have high phosphate levels [42].

This relationship is probably a direct consequence of diet. People who are poor and live in urban environments consume cheaper processed and fast foods that contain phosphate additives [42].

Symptoms and Signs

If you have mild hyperphosphatemia, you probably won’t experience any symptoms.

However, if caused by severe kidney disease, you may also have low calcium levels in the blood (hypocalcemia). Low calcium levels can cause [43, 44]:

  • Muscle cramps and spasms (tetany)
  • Bone weakness
  • Chalk-like calcium deposits (calcification) in tissues. Deposits within the walls of blood vessels can lead to a hardening of the arteries.
  • Severe itching

Severe complications include [3]:

  • High resting heart rate (tachycardia)
  • Low blood pressure (hypotension)
  • Heart attack
  • Coma

Health Effects

1) Heart Disease

High phosphate binds calcium and forms crystals (calcium phosphate) that can accumulate in various tissues. In the blood vessels, their buildup (calcification) may cause damage or hardening [3, 45, 46].

In a large study of over 110,000 people, both low and high blood phosphate levels were linked to an increased risk of heart disease. Higher levels within the normal range also increased the risk [47].

In another study of over 2,500 people, higher-range normal levels (> 3.6 mg/dL) were linked to a 1.5X higher risk of calcification in the arteries, while levels above 4 mg/dL increased the risk by over 2X [48].

High levels are linked to both heart risks in healthy people and heart complications in those with heart disease. In over 3,000 healthy people, each 1 mg/dL increase in phosphate levels raised the risk of heart disease by 1.3X. In over 4,000 people with heart disease, higher levels were linked with a greater risk of heart failure and heart attacks [49, 50].

2) Chronic Kidney Disease

In a study of over 2,000 healthy people, phosphorus above 4 mg/dL was associated with double the risk of developing chronic kidney disease [51].

3) Fractures

In over 12,000 people, higher blood phosphorus levels, even within the normal range, were linked with increased fracture risk in both men and women [52].

Many other studies looked at this relationship by focusing on dietary phosphate intake instead of the blood levels. As dietary phosphate intake increases, bones are broken down more and rebuilt less [53, 53, 54, 55].

Strong bones require a balance between phosphorus and calcium levels. High dietary phosphorus can throw this balance off. In 85 postmenopausal women, consumption of one or more bottles per day of phosphoric acid-containing soft drinks (such as coke) was associated with lower calcium levels [56].

4) Cognitive Function

In a study of over 5,500 men, higher baseline blood phosphate was associated with higher odds of poor executive function 4 years later [57].

High phosphate levels may weaken the blood-brain barrier, which can have a major effect on brain function. In a study of 186 people, phosphate levels > 3.9 mg/dL were linked with 3.7 higher odds of brain lesions, likely resulting from a weakened blood-brain barrier [45].

5) Infections

In over 1,000 dialysis patients, infections were more frequent among those with high phosphate levels [58].

6) Aging

Animal studies show that high phosphate levels can accelerate the aging process by triggering tissue damage. In mice, high phosphate caused premature aging symptoms such as weight loss, spine deformities, decreased production of sex hormones, infertility, muscle wasting, skin thinning, and reduced life span [59].

In over 7,000 people, higher phosphate levels were linked to an age-related decrease in muscle strength in those over 65 years old [60].

7) Cancer

The relationship between high phosphate levels and cancer is not straightforward. High phosphate levels are mostly linked to an increased risk of cancer, but they may also decrease the risk in some cases. High levels may be more detrimental for men than for women, although this is still uncertain.

In almost 400,000 people, higher phosphate levels were linked to higher overall cancer risk in men. High levels were associated with an increased risk of pancreatic, lung, thyroid, and bone cancer in men, and esophagus, lung, and nonmelanoma skin cancer in women. Conversely, the risk of breast, endometrial, and other endocrine cancers dropped with higher phosphate levels in both sexes [61].

In over 47,000 men, higher dietary phosphorus was associated with greater risk of total, deadly, and high-grade prostate cancer [62].

In a small study of 100 people, all cancer patients had high phosphate levels [38].

Feeding mice with a diet high in phosphate stimulates the growth of lung tumors, both in number and size [63].

8) Mortality

In a study of almost 13,000 people, high blood phosphate levels were linked to increased mortality [64].

In over 42,000 hospitalized patients, phosphate levels on either end of the extreme range (high or low) were linked to in-hospital deaths. Low levels increased the risk by 1.6 times, while high levels increased the risk by up to almost 4 times. In a smaller study on 4,000 people with heart disease, blood phosphate over 3.5 mg/dL increased the risk of death by 1.3 times [65, 50].

In almost 1,000 people, baseline phosphorus > 3.9 mg/dL was associated with an increased risk of death from heart disease over the next 5 years [66].

Some studies found that this link holds true only in men. In 6k people monitored for over 10 years, phosphate was linked to deaths only in men [67].

In another study on over 1,300 older men, higher phosphorus levels (≥ 3.6 mg/dL) increased the risk of death from any cause by 1.6 times. In an 18-year follow-up study of over 2,500 people with high blood pressure, diabetes, and/or obesity, higher phosphate levels were associated with more deaths in men [68, 69].

Phosphorus intake alone may increase the risk regardless of blood levels. In over 9,600 healthy adults, higher phosphorus intake was associated with higher deaths from any cause in those who consumed > 1400 mg/day of phosphorus [70].

Decreasing phosphorus levels may lower the risk. In over 6,700 patients with chronic kidney disease on dialysis, phosphate-binding agents decreased deaths from heart disease or other causes by over 20% [71].

Decreasing Blood Phosphorus

The most important thing is to work with your doctor to find out what’s causing your high phosphate and to treat any underlying conditions!

Discuss the additional lifestyle changes with your doctor. None of these strategies should ever be done in place of what your doctor recommends or prescribes!

Eat foods that are low in phosphorus to maintain blood phosphate levels within a healthy range. Avoid protein-heavy and dairy products. Most importantly, eliminate foods that contain phosphate additives (cooked ham, roast breast turkey/chicken) and soft drinks. Processed food can have up to 70% higher phosphate content than non-processed alternatives [21, 72, 73].

Adopting a plant-based diet may help, as studies suggest that phosphate is less readily-absorbed from plants, especially those containing phytates [74, 14].

Avoid night-time snacks! In a study of 14 healthy men, night-time snacking increased baseline blood phosphorus levels, by reducing phosphorus flushing via the kidneys [75].

Decrease or quit smoking [29, 30].

Make sure you are properly hydrated [28].

Avoid using enemas that contain phosphate salts. Your body can absorb these salts, leading to excess phosphate levels in the blood [76].

If you have uncontrolled diabetes, it is critical to bring it under control with diet, exercise, and prescribed therapy [77].

If your phosphate levels high, your doctor will usually prescribe fluids (unless you have kidney failure). If your levels have been high for a long time, phosphate binders such as aluminum and magnesium salts can reduce the phosphate load. These do have side effects and can only be used in a limited capacity [1].

Discuss the following supplements with your doctor:

  • Niacin/nicotinamide (vitamin B3) [78, 79, 80, 81, 82] *niacin can decrease platelet count below normal, so it needs to be monitored
  • Vitamin C [83]
  • Phosphate-binding supplements, like calcium carbonate can be taken with meals, if necessary (e.g. in kidney disease), to reduce the absorption of phosphate [44, 84]

Further Reading

Phosphate (Phosphorus) Blood Test + Low Levels

About the Author

Biljana Novkovic

Biljana Novkovic

PhD
Biljana received her PhD from Hokkaido University.
Before joining SelfHacked, she was a research scientist with extensive field and laboratory experience. She spent 4 years reviewing the scientific literature on supplements, lab tests and other areas of health sciences. She is passionate about releasing the most accurate science and health information available on topics, and she's meticulous when writing and reviewing articles to make sure the science is sound. She believes that SelfHacked has the best science that is also layperson-friendly on the web.

Click here to subscribe

RATE THIS ARTICLE

1 Star2 Stars3 Stars4 Stars5 Stars
(No Ratings Yet)
Loading...

FDA Compliance

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.