Importance of Vitamin A


Vitamin A deficiency is the most common preventable disease that avian veterinarians see in their practice Pet birds that eat only seeds (especially sunflower seeds and peanuts) are most prone to this problem. Vitamin A deficiencies increase the likelihood of secondary infections because cells that line the respiratory, reproductive and digestive tracts undergo structural change, which allows bacteria and microorganisms to penetrate the mucous membrane barriers.

The respiratory system is most often affected. A bird with vitamin A deficiency may show any of the following symptoms: sneezing, wheezing, nasal discharge, crusted or plugged nostrils, lethargy, depression, diarrhea, tail-bobbing, thinness, poor feather color, swollen eyes, ocular discharge or lack of appetite.

Though few birds actually die from vitamin A deficiency, they do die from the secondary infections common to birds with weakened resistance. Vitamin A strengthens cells so that they function properly and it enables the natural healing process to occur. An ounce of prevention is worth a pound of cure.


Further, in birds there is a complex relationship among calcium, phosphorus and vitamin D. Calcium is the major component of the skeleton and eggshell and is also present in the blood Calcium is absorbed in the intestines and vitamin D regulates that absorption. When the calcium level in the blood stream is low, vitamin D increases the absorption rate. Vegetables that contain oxalates, such as spinach, rhubarb and others, interfere with calcium absorption. High fat diets also block calcium absorption.

Phosphorus is also a component of bone and is absorbed through the intestines. There is an inverse relationship between phosphorus and calcium. If the calcium level in the bloodstream is low, more phosphorus is absorbed. If the calcium is high, less phosphorus is absorbed. Vitamin D increases the absorption of phosphorus through the intestines when the blood level of phosphorus is low.

For healthy bones, the ratio of calcium to phosphorus in the food should be about 2:1 The greater the variation from this ratio, the greater the role of vitamin D in regulating calcium and phosphorous. Fortunately, about 30% of the phosphorus present in food is available in a form that can be utilized by birds. But too much phosphorus interferes with calcium absorption.

Generally, foods that are yellow, orange or deep green in color have high vitamin A content Corn. lettuce, summer squash, grapes, apples, oranges and bananas are exceptions and are low in this vitamin.

Birds can make their own vitamin D if they have access to sunshine (not filtered by glass.) Birds cannot absorb calcium without vitamin D. Birds housed indoors on an all-seed diet lack vitamin D and calcium (and are likely to die at a young age.)

Cuttlebone is an excellent source of calcium. Full-spectrum fluorescent lights (such as Vita-Lites) that are suspended over your bird cages will allow your birds to make their own vitamin D.

If your birds are on a peletted diet, then you don’t have to worry about either calcium or vitamin D.

NOTE. In African Greys, the Calcium:Phosphorus ratio should be 2:1. If they do not get the proper ratio, they may be prone to falling off their perch, lack of coordination and seizures.

WARNING: Too much vitamin D or too much vitamin A can be harmful. Too much vitamin D causes too much absorption of calcium which results in minerals being deposited in soft tissue including kidneys. Too much vitamin A can be toxic and results in hypervitaminosis A. Bone spurs, painful joints, liver damage and renal gout are a few health problems that can result.

Vitamin A Content          IU Per 100 GRAMS 

Red Chili peppers (fresh)                21,000
Red chili peppers (dried)                77,000
Broccoli leaves                          16,000
Broccoli flowers                          3,000
Carrots (pureed)                         10,000
Sweet Potatoes                            9,000
Collards                                  9,300
Kale                                     10,000
Dandelion greens                         14,000
Spinach                                   8,000
Beef liver                               45,000
Egg yolks                                 3,000
Cantaloupe                                4,000
Turnip Leaves                             7,600

Canned pumpkin and Jalapeno peppers are good sources of Vitamin A.

The best natural foods which contain a good calcium:phosphorus level for African greys are:

broccoli, collard leaves, dandelion greens, fennel, okra, orange with the peel, parsley, spinach, turnip leaves, kelp and blackstrap molasses.