Hi Beachy,
The healthy body keeps substances like phosphorus in a tight range in the blood for a reason–bad things happen whether the levels are too high or too low. Here is some info I found on-line in the Merck Home Manual:
Hypophosphatemia
In hypophosphatemia, the level of phosphate in the blood is too low. Chronic hypophosphatemia occurs in people who have hyperparathyroidism, hypothyroidism (an underactive thyroid gland), or impaired kidney function or who use diuretics for a long time. Taking large amounts of aluminum-containing antacids for a long time or large amounts of the drug theophylline can also deplete the body’s stores of phosphate. Phosphate stores are depleted in people with severe undernutrition, diabetic ketoacidosis, severe alcohol intoxication, or severe burns. The level of phosphate in the blood can fall dangerously low very quickly in people recovering from these conditions, because the body uses large amounts of phosphate during recovery.Symptoms occur only when the phosphate level in the blood falls very low. Muscle weakness progresses to stupor, coma, and death. With prolonged mild hypophosphatemia, the bones can weaken, resulting in bone pain and fractures. The diagnosis is made by determining that the phosphate level in the blood is low.
Drinking one quart of low-fat or skim milk, which provides a large amount of phosphate, may help. A person with mild hypophosphatemia and no symptoms can take phosphate by mouth, but doing so usually causes diarrhea. If hypophosphatemia is very severe or if phosphate cannot be taken by mouth, intravenous phosphate may be given.