Phosphorus (Phosphate)

Recommended Daily Intake

According to the U.S. Institute Of Medicine (IOM), Recommended Dietary Allowance (RDA) for phosphorus for adults is 700 mg per day ^[1]. Healthy individuals, including vegans and pregnant women, can easily get enough phosphorus from common plant or animal foods. Breast milk contains enough phosphorus for exclusively breastfed infants 0-6 months old ^[1,7,27].

Table 1. Recommended Dietary Allowance (RDA) for phosphorus Source: the U.S. Institute Of Medicine (IOM) [1]
AGE	RDA (mg)
Infants 0-6 months	100 (AI)*
Infants 7-12 months	275 (AI)*
Children 1-3 years	460
Children 4-8 years	500
Children 9-18 years, including pregnant and breastfeeding girls	1,250
Adults, 19 years and older, including pregnant and breastfeeding women	700

* AI = Adequate Intake

Foods High in Phosphorus

The richest sources of phosphorus are foods with phosphate additives: fast food, cheese, canned foods.

Picture 1. Phosphorus-rich sources

Table 2. Foods rich in phosphorus (a non-complete list) Source: U.S. Department of Agriculture (USDA) [7]
ANIMAL FOODS	PHOSPHORUS (mg)
Cheese: goat, pasteurized/American, romano (100 g)	650-900
Cheese, semi/hard: blue, brick, Camembert, caraway, cheddar, colby, edam, feta, gouda, gruyere, limburger, Mexican, Monterey, provolone, Swiss, tilsit (100 g)	350-600
Fast food: burrito, hamburger, pizza, hot dog (1 serving)	100-600
Sardines, with bones (1 can, 92 g)	450
Sheep milk (8 oz, 237 mL)	400
Organ meats: brain, heart, kidney, liver (beef, chicken, lamb, pork, turkey) (3 oz, 85 g)	200-400
Formulated bar (2 oz, 57 g)	150-350
Seafood: fish (salmon, cod, pollock, shark, trout, tuna, walleye), mollusks (abalone, clams, cuttlefish, mussels, octopussi, oysters, scallops, shrimps, squids, whelks), crabs, lobsters (3 oz, 85 g)	150-350
Chocolate shake (12 oz, 237 mL)	300
Pancake, dry mix, with buttermilk (52 g)	300
Milk: cow/goat/buffalo, fat/nonfat/chocolate (1 cup, 237 mL)	200-300
Meat: beef, buffalo, chicken, venison (deer), goat, lamb, pork/bacon, rabbit, turkey (3 oz, 85 g)	150-300
Eggnog (1 cup, 254 g)	250
Snails (3 oz, 85 g)	230
Whey, acid, fluid (1 cup, 237 mL)	200
Pancakes, from recipe (3 pancakes, 120 g)	200
Egg (2 eggs, 2 x 50 g)	150-200
Milk chocolate (50 g)	100-200
Custard, egg (1/2 cup, 144 g)	180
Cold cuts: bologna, ham, pepperoni, salami (2 oz, 57 g)	100-150
Pudding (1/2 cup, 4 oz, 120 mL)	50-120
Caviar (1 oz, 28 g)	100
PLANT FOODS
Meatless meatballs, sausage or fish sticks (1 cup, ~140 g)	300-650
Seeds: pumpkin, squash, sunflower (1 oz, 28 g)	330
Biscuits (2 oz, 57 g)	200-330
Morning cereals, ready-to-eat (1 cup, ~30 g cereals + water)	0-300
Soybeans (1/2 cup, 90 g)	200-300
Tempeh (1 cup, 170 g)	200
Waffles (2 pieces, 70 g)	200
Oatmeal, instant (1 cup, 234 g, prepared)	200
Potato (middle size, 200 g)	200
Popcorn (2 oz, 57 g)	150-200
Beans (adzuki, black turtle, kidney, lima, mothbeans, mungo, navy, pink, small white, yardlong, yellow, winged), peas, chickpeas, lentils (1/2 cup, 90 g)	100-200
Nuts: almonds, brazil nuts, cashews, hazelnuts, peanuts, pecans, pine-nuts, pistachios, walnuts (1 oz, 28 g); chestnuts (1 cup, 140 g)	100-200
Mushrooms (1 cup, 150 g)	Up to 200
Beer (1 can, 12 oz, 355 mL) [15]	Up to 175
Fruit juice (1 can, 12 oz, 355 mL) [15]	Up to 175
Rice, brown (1 cup, 150 g)	150
Crackers, wheat (2 oz, 57 g)	150
Bread, whole wheat (2 slices, 60 g)	150
Bagel, wheat (100 g)	150
Tofu (1 oz, 28 g)	100-150
Tortilla chips (2 oz, 57 g)	100-150
Wild rice (1 cup, 164 g)	135
Peanut butter (2 tbsp, 30 g)	100-130
Bread, chapati, roti, commercial (1 piece, 70 g)	125
Bread, pita (6-1/2″, 100 g)	120
OTHER
Baking powder (1 packet, 10 g)	700-900
Baker’s yeast (1 packet, 17 g)	350
Powders to prepare beverages (1 serving)	0-300
Soft drinks: cola with phosphoric acid (1 can, 12 oz, 355 mL) [15]	0-175
Ice tea (1 can, 12 oz, 355 mL) [15]	0-130

NOTE: Phosphorus content of food products may vary greatly among brands.

Foods Low in Phosphorus

Common foods low in phosphorus include white bread, rice, pasta, fresh fruits, most vegetables and water.

Table 3. Foods low in phosphorus (a non-complete list) Source: U.S. Department of Agriculture (USDA) [7]
PLANT FOODS	Phosphorus (mg)
Barley, pearled (1 cup, 160 g)	85
Macaroni (1 cup, 140 g)	80
Pastries (1 piece, 80 g)	50-80
Bulgur (1 cup, cooked with water)	75
Pretzels, hard, unsalted (2 oz, 57 g)	70
Rice, white (1 cup, 190 g)	70
Bread: French, Italian, pumpernickel, raisin, white (2 slices, 60 g)	60-70
Corn, sweet, yellow, canned (1/2 cup, 82 g)	60
English muffin (1 oz, 28 g)	50
Noodles, Japanese (1 cup, 176 g)	50
Malt syrup (1 tbsp, 21 g)	50
Cookies without nuts or chocolate (2 oz, 57 g)	20-50
Vegetables: alfalfa, asparagus, butterbur, cabbage, carrots (cooked), cauliflower, chayote, collards, dandelion, kale, leeks, lettuce, mustard greens, okra, onion, peppers, rhubarb, squash (summer), turnip/greens, water chestnut, watercress (1/2 cup)	10-50
Pie: apple, cherry, peach (1 piece, 125 g)	5-40
Couscous (1 cup, 160 g, cooked)	35
Fruits, fresh: apple/applesauce, blueberries, boysenberries, clementines, cherries, cranberries, grapes, lemon, lime, mango, pear, pineapple, plums, raspberries, tangerine (mandarin oranges), watermelon (1/2 cup)	10-35
Wine (1 glass, 5 oz, 150 mL)	Up to 35
Gelatin dessert (1/2 cup, 4 oz)	30
Jicama (200 g)	30
Cereals: corn flakes, corn grits, farina, rice crisps (1 cup, cooked with water)	10-30
Beans, snap, green/yellow (1/2 cup, 60 g)	10-20
Spices: anise, chili, coriander, cumin, curry, dill, fennel, garlic, ginger, mustard, nutmeg, onion, paprika, pepper, turmeric (1 tsp)	Up to 20
Syrups: cane, corn, grenadine, maple (1 tbsp, 20 g)	0-15
Jam (1 tbsp, 20 g)	10
Tapioca, pearl, dry (1 cup, 152 g)	10
Arrowroot flour (1 cup, 128 g)	10
Candies, hard, jellybeans, toffee (1 oz, 28 g)	1-10
Coffee (1 cup, 8 oz, 237 mL)–limit to 1 cup/day to prevent high potassium intake	Up to 10
Tea (1 cup, 237 mL)–limit to 2 cups/day to prevent high potassium intake	0-2
Margarine (1 tbsp, 14 g)	1
Vinegar, all types (1 tbsp, 15 g)	1
Municipal water (1 cup, 237 mL)	0-1
Table sugar, white/brown (1 tsp, 3 g)	0
Vegetable oils (1 tbsp, 14 g)	0
Carbonated beverages: club soda, ginger ale, lemon-lime, orange, tonic water, root beer (12 oz, 237 mL)	0
ANIMAL FOODS
Cheese: cream, cottage, ricotta (2 tbsp, 30 g)	30-50
Cream, liquid, half and half (1 fl oz, 30 mg)	10-45
Cake, fruit (1 piece, 65 g)	35
Salad dressing: caesar, Italian, mayonnaise, French, Russian (2 tbsp, 30 g)	Up to 30
Sour cream (1 tbsp, 12 g)	10
Honey (1 tbsp, 20 g)	1

A Low-Phosphorus, Potassium and Sodium Diet in Chronic Kidney Disease

If you have a chronic kidney disease with phosphate retention, your doctor may recommend you to limit phosphorus intake to 800-1,000 mg per day ^[38]. The foods listed in the Table 3 above are low in phosphorus (<100 mg/serving), sodium (<300 mg/serving), potassium (<200 mg/serving) and protein, but your doctor should provide you with a list of foods appropriate for you personally.

High blood phosphate levels in individuals with chronic kidney disease are associated with increased mortality ^[15]. On the other hand, a low-phosphorus diet, which is usually low in protein, may lead to protein-energy wasting, which was, in one study from y. 2008, also associated with increased mortality ^[44]. This means everyone on a low-protein diet should take care to get enough proteins, but again, your doctor should tell you how much phosphorus and protein you can take. Some researchers suggest avoiding only foods with phosphate additives but not foods with naturally present phosphate ^[15].

Phosphate Food Additives with E-Numbers

Many commercially prepared foods, such as fast food, canned fish, commercial baked goods and cola, contain phosphate additives. The amount of phosphorus in these foods is usually not listed on the nutrition fact labels and in nutrient databases like USDA.gov, so, if you have a kidney disease, ask your doctor or dietitian, how much of these foods you can eat; you usually do not need to avoid them completely. On the food labels in Europe, food additives may be listed only with E-numbers and not with their full names.

• E322  Lecithins
• E338  Phosphoric acid
• E339  Sodium phosphates
• E340  Potassium phosphates
• E341  Calcium phosphates
• E343  Magnesium phosphates
• E450  Diphosphates or pyrophosphates
• E451  Triphosphates
• E452  Polyphosphates
• E541  Sodium aluminium phosphate (acidic sodium aluminium phosphate is used in a baking powder [leavening agent] and alkaline sodium aluminium phosphate as a food additive in processed cheese ^[19].
• E542  Edible bone phosphate (used as anticaking agent and water-retaining agent)
• E1410  Monostarch phosphate
• E1412  Distarch phosphate
• E1413  Phosphated distarch phosphate
• E1414  Acetylated distarch phosphate
• References: ^[6]

Phosphorus Absorption

We absorb 10-50% of organic phosphorus naturally present in plant foods, about 50% of organic phosphorus naturally present in animal foods and 80-100% of inorganic phosphorus from phosphate food additives and dietary supplements ^[26,27]. This means, foods with phosphate additives may be the richest sources of phosphorus that is actually absorbed.

Phosphorus is absorbed in the small intestine ^[27,42].

Phosphate Binders

Phosphate binders, such as calcium acetate or carbonate, sevelamer hydrochloride, lanthanum carbonate, and aluminium or magnesium hydroxide, are drugs that, when taken with meals, bind phosphorus from foods and partially prevent its absorption ^[30,31]. They are used to prevent high blood phosphate levels in individuals with chronic kidney disease

Is too much phosphorus from foods and drinks bad for you?

Bone Health

Diet high in both phosphorus and calcium has not been proven harmful for bones in healthy individuals. Diet high in phosphorus and low in calcium could theoretically result in osteoporosis (low bone density), but more research is warranted ^[1,27].

Teeth

It seems that the risk of tooth decay depends more on the sugar than phosphoric acid content of cola ^[36,37].

Kidney Stones

There is insufficient evidence about the effect of either high- or low-phosphorus diet on the kidney stones risk ^[40]. In one study from y. 1992 ^[41], but not in another one from y. 2007 ^[25], regular consumption of soft drinks with phosphoric acid was associated with increased risk of kidney stones. A low-phosphorus, low-calcium diet has not been found very effective in prevention of infected, phosphate-containing kidney stones (struvite stones) ^[29].

Phosphate Supplements

Phosphate supplements are mainly used to correct or prevent low blood phosphate levels in severely malnourished persons, chronic alcoholics, individuals with uncontrolled diabetes mellitus and after the removal of the overactive parathyroid glands.

Available forms:

• Oral:
  • Over-the-counter (OTC): sodium and potassium phosphate alone as tablets and capsules or as part of multivitamin/mineral supplements
  • By prescription: potassium phosphate powder for solution, mainly for prevention of calcium urinary stones ^[13,24]
• Intravenous infusion (by prescription): sodium and potassium phosphate

Dosage

Typical doses of phosphate supplements to treat hypophosphatemia are 1-3 grams per day; it is your doctor who can prescribe appropriate dose for you, though.

Phosphate salts are LIKELY INEFFECTIVE for improving aerobic exercise performance ^[24].

There is INSUFFICIENT EVIDENCE about phosphate salts effectiveness in sensitive teeth, heartburn, severe burns, hyperparathyroidism, vitamin D resistant rickets, as a laxative for bowel preparation before colonoscopy ^[24], and in prevention of calcium kidney stones in individuals with increased calcium excretion into the urine (hypercalciuria) ^[49].

Safety: Side Effects, Toxicity

The Tolerable Upper Intake Level (UL) for phosphorus–the amount that should not cause side effects–is 3,000-4,000 mg/day ^[1]. The UL does not apply to individuals with kidney failure in which maximal allowed phosphate intake should pbe determined individually. Occasional use of phosphate salts is likely safe for most people, but long-term use should be monitored by a doctor ^[24].

Possible side effects of oral or intravenous phosphate supplements may include nausea, diarrhea, bone or joint pain, muscle twitching (tetany) or cramps, headache, convulsions, irregular heartbeat, numbness or tingling around the lips, hands and feet ^[12,24]. Rarely, various ingredients of the supplement preparation can trigger severe allergic reaction (anaphylactic reaction) with hives, swollen face and lips and difficulty breathing ^[13].

Intravenous phosphates may, rarely, decrease white blood cells count ^[10]. The use of intravenous sodium phosphate along with thiazide diuretics may cause kidney damage ^[11].

During Pregnancy

According to the U.S. Food and Drug Administration (FDA), phosphate supplements are pregnancy category C, which means, harmful effects for the babies are not known due to lack of human studies ^[11]. Sodium phosphate in pregnancy should be used only when clearly needed. According to Natural Medicines Comprehensive Database, phosphate salts in doses within RDA are likely safe during pregnancy and breastfeeding ^[24].

Overdose

Phosphate supplements overdose may cause electrolyte disturbances: hyperphosphatemia, hypocalcemia, hypomagnesemia, hypokalemia, hyperkalemia, hypernatremia or metabolic acidosis. Other acute complications include acute kidney failure, severe hypotension, acute kidney failure or even death ^[24].

Who should avoid phosphate supplements?

• Speak with your doctor if you intend to use phosphate salts and you have a heart, liver, kidney, lung or thyroid disease or leg swelling (edema) of any cause. Phosphate supplements may worsen burns, pancreatitis, rickets, osteomalacia, underactive parathyroid or adrenal glands and toxemia of pregnancy ^[24].
• Phosphate salts should not be used in hyperphosphatemia, hypocalcemia and hypernatremia [sodium phosphate] or hyperkalemia [potassium phosphate].
• References: ^[11,24]

Phosphate-Drugs Interactions

• Supplements and drugs that reduce phosphate absorption: calcium, magnesium and aluminium antacids, iron supplements, the anticonvulsant phenytoin and bile acid binders cholestyramine and colestipol.
• Phosphates can reduce the absorption of iron, calcium and magnesium.
• References: ^[1,24,35]

Phosphates as Saline Laxatives (Enemas)

“Sodium biphosphate/sodium phosphate” is used as an osmotic laxative (as tablets or enema) to treat constipation, to prepare for colonoscopy or to restore bowel activity after surgery. It can be absorbed in the colon and cause hyperphosphatemia, hypocalcemia or acute kidney injury or even death ^[8,24].

Regulation of Blood Phosphate Levels

Blood phosphate levels are closely related to calcium levels and are regulated mainly by parathormone, vitamin D and Fibroblast Growth Factor 23 (FGF23).

Normal Blood Phosphate Range

Normal blood phosphate level range in adults = 2.5-4.5 mg/dL or 0.8-1.4 mmol/L ^[4].

References: PubMed and online medical journals

Phosphate Urine Test

Phosphate urine test measures the amount of phosphate excreted in urine over 24 hours. The test can be done to find the cause of abnormal blood phosphate or calcium levels or to evaluate kidney damage in chronic kidney disease, to find the cause of kidney stones, rickets or osteomalacia. The test results should be interpreted along with urine and blood levels of calcium, vitamin D and other substances.

Normal 24-hour urine phosphate range: 400-1,300 mg or 12.9-42 mmol ^[47] (may differ among laboratories)

Causes of increased urine phosphate (hyperphosphaturia):

• Ingestion of large amount of foods high in phosphorus (milk, cheese, meat), diet high in fructose (at least 20% of total calories) or low in calcium or potassium
• Medications: phosphate supplements or laxatives, diuretics (acetazolamide), corticosteroids, parathormone
• Phosphorus poisoning
• Diseases: untreated diabetes mellitus, hyperparathyroidism, cancer, hypophosphatemic rickets, Fanconi syndrome, hereditary fructose intolerance
• References: ^[1,45,48,50]

High amount of phosphate in the urine, for example, after drinking large amounts of milk, which is high in phosphorus and calcium, can result in formation of phosphate crystals in urine and cloudy urine ^[45]. A drop of acetic acid (vinegar) immediately clears urine that is cloudy due to phosphates. Increased phosphate excretion into urine by itself is not harmful but it may increase the risk of calcium kidney stones ^[23].

Causes of decreased urine phosphate:

• Diet low in phosphate or high in potassium
• Medications: phosphate binders, aluminium antacids
• Diseases: chronic kidney disease, intestinal malabsorption diseases, hypoparathyroidism, vitamin D deficiency
• References: ^[48]

Frequently Asked Questions

1. Are phosphate supplements and food additives vegan?

• In the United States, all phosphates, except edible bone phosphate, are produced from minerals, so they are vegan ^[2,6,19,22]; they are also Generally Recognized As Safe (GRAS) by the U.S. Food and Drug Administration (FDA) ^[14]. In the European Union, phosphates may be derived from animals, but usually from minerals, so they are “typically vegan” ^[2,6,19,22].
• Edible bone phosphate (E542) is derived from animal bones, so it is not vegan; it is also not GRAS ^[21].

2. What is the optimal phosphorus/calcium ratio in the diet?

As long as you consume enough of phosphorus and calcium, phosphorus/calcium ratio in your diet is probably not significant for your health ^[27].