Importance of Minerals and Vitamins in the Diet

In the early 60’s and 70’s, many hundreds of thousands of baby Red-eared sliders were sold as children’s pets. It was during this time that the effects of improper diet for turtles became appallingly obvious. Soft shells, deformed shells and paralyzed legs were common in many of the sliders. As breeders, veterinarians and researchers began to look into the problem, the mineral calcium (Ca) became the first choice to cure the deficiency. Calcium blocks were produced and sold but the problem didn’t go away. More research showed that the absorption of calcium was controlled by several biochemical factors. Not only was calcium necessary, but the proper amounts of phosphorus (P) and vitamin D3 were needed. Each of these vital elements and compounds will be discussed briefly, but the real purpose of this chapter is to teach you which foods contain the proper nutrition for Box turtles.

Calcium—a mineral that is obtained from foods or supplements. Calcium is absorbed by the blood system through the turtle’s intestine and stays dissolved in the blood until it is used by the body to build bones or for other organ functions. For calcium to be used by the body, a proper level of phosphorus and vitamin D3 is required. If a turtle does not get enough calcium, it will try to maintain a blood Ca:P blood level of 2:1 by stealing calcium from its own bones, causing metabolic bone disease.

Phosphorus—a mineral found in abundance in foods that turtles eat. Therefore it is not usually necessary to supplement phosphorus. A calcium supplement without phosphrous and which contains Vit D3 is best to use.

Vitamin D3—a vitamin that is produced by pigment cells in the skin and shell when a box turtle is in sunlight or other UVB producing light source. The vitamin is necessary for the conversion of calcium into useable compounds. Therefore buy calcium supplements that contain Vit D3.

Vitamin A—a fat-soluble vitamin that is essential for good vision and health. It is found in foods that are orange fleshed like carrots, sweet potatoes, winter squashes, dark, leafy greens and cod liver oil. A deficiency of vitamin A can lead to eye infections and upper respiratory disease. Vitamin A rich food should be provided regularly.

In the wild, a box turtle will have a large area in which to roam and forage for food and it would likely find all the nutrients its body needs. A deficiency would be unlikely, and many long-time turtle keepers will tell you that most wild turtles are very healthy. As penned pets, our turtles don’t have the opportunity to forage on a lot of different things, and it’s up to the owner to provide the correct diet. For optimum health, a turtle should get the proper types and amounts of food items. The turtle should be given a "square meal" which contains protein, carbohydrates, fiber, calcium, and vitamins. An animal that doesn’t receive the correct diet can succumb to various diseases, metabolic bone disease, organ failure, and immune-suppression diseases.

It would be nice if we could insure that our box turtle is getting everything it needs from diet alone, but that’s not usually the case. No one has ever observed a wild box turtle from the moment of hatching and written down everything it eats. If someone does in the future, we’ll come a long way in understanding the nutritional needs of box turtles. We do know the Ca:P ratio of foods is important and therefore have provided a list of foods and their ratios. Regularly use foods with a high Ca to P ratio and avoid foods with a high P to Ca ratio, and foods high in oxalic acid. The food items at the end of the list should be use sparingly. If they are used, add calcium supplements without additional phosphrous to bring the calcium levels higher. However, this list should not be used exclusively to construct your turtle’s diet. Remember to include insects or other protein sources.


Key: A listing of "2.00" in the Ca:P column represents a ratio of 2:1 and is good. The lower this number is, the worse the Ca:P ratio and the less it should be used in the diet. Most of this data come from the USDA. You can check the nutritional content of other food items at their website USDA.

Food Item       Prep   Serving wt(gms)  Ca(mg)	P(mg)	Ca:P

collards        raw     1 cup 	36	52	3.6	14.4
roselle	        raw	1 cup	57	123	21	5.86
lambsquarters   boiled  1/2 c	90	232	41	5.66
papaya	        raw	1 med	304	72	16	4.50
turnip greens	raw     1/2 c   28	53	12	4.42
coriander       raw	1/4 c 	4	4	1	4.00
rose apple      raw     3.5 oz  100	29	8	3.63 
parsley	        raw	1/2 c   30	39	12	3.25
amaranth        boiled  1/2 c	66	138	47	2.94
dandelion green	raw     1/2 c   28	52	18	2.89
cabbage, Chineseraw     1/2 c   35	37	13	2.85
beet greens     boiled  1/2 c	72	82	29	2.83
lettuce, loose-leafraw  1/2 c   28	19	7	2.71
kale	        boiled	1/2 c   65	47	18	2.61
figs	        raw	1 med   50	18	7	2.57
pricklypear     raw	1 med   103	58	25	2.32
orange, Valenciaraw     1 med   121	48	21	2.29
chicory greens	raw     1/2 c	90	90	42	2.14
figs	        dried	10 figs 187	269	128	2.10
orange, navel	raw	1 med   140	56	27	2.07
cabbage, green	raw	1/2 c	35	16	8	2.00
carissa	        raw	1 med   20	2	1	2.00
kumquat	        raw     1 med   19	8	4	2.00
spinach(don't use)raw	1/2 c   28	28	14	2.00
watercress      raw	1/2 c   17	20	10	2.00
onions, spring	raw     1/2 c   50	30	16	1.88
endive	        raw	1/2 c   25	13	7	1.86
lime	        raw	1 med	67	22	12	1.83
raspberries     raw	1 cup	123	27	15	1.80
sapodilla       raw	1 med	170	36	20	1.80
mustard greens	boiled	1/2 c   70	52	29	1.79
chard, Swiss	boiled	1/2 c   88	51	29	1.76
leeks		raw	1/4 c   26	15	9	1.67
lemon		raw	1 med	58	15	9	1.67
grapefruit	raw	1/2 med 118	14	9	1.56
blackberries	raw	1/2 c	72	23	15	1.53
tangerine	raw	1 med	84	12	8	1.50
grapes(slip skin)raw	1 cup	92	13	9	1.44
celery		raw	1 stlk  40	14	10	1.40
sapote		raw	1 med	225	88	63	1.40
tofu		uncooked1/2 c	61	49	37	1.32
green beans 	boiled	1/2 c	62	29	24	1.21
cabbage, red	raw	1/2 c   35	18	15	1.20
turnip		boiled	1/2 c   78	18	15	1.20
crabapple	raw	1 cup 	110	20	17	1.18
eggplant	raw	1/2 c   41	15	13	1.15
garlic		raw	3 clves	9	16	14	1.14
radish		raw	10 rdsh	45	9	8	1.13
okra		boiled	1/2 c   80	50	45	1.11
acerola		raw	1 cup	98	12	11	1.09
tofu		raw	1/2 c	124	130	120	1.08
pear		raw	1 med   166	19	18	1.06
mulberries	raw	1 cup	140	55	53	1.04
apple, w/skin	raw	1 med 	138	10	10	1.00
lettuce, icebergraw	1 leaf	20	4	4	1.00
persimmon	raw	1 med	25	7	7	1.00
pineapple	raw	1 cup 	155	11	11	1.00
elderberries	raw	1 cup	145	55	57	0.96
mango		raw	1 med	207	21	22	0.95
gooseberries	raw	1 cup	150	38	40	0.95
currants, black	raw	1/2 c	56	31	33	0.94
watermelon	raw	1 cup	160	13	14	0.93
cranberry	raw	1 cup 	95	7	8	0.88
honeydew melon	raw	1/4 c	100	14	16	0.88
grapes(adherent skin)raw1 cup	160	17	21	0.81
cabbage, savoy	raw	1/2 c   35	12	15	0.80
guava		raw	1 med	90	18	23	0.78
cucumber	raw	1/2 c   52	7	9	0.78
cherry		raw	10 chrs	68	10	13	0.77
lettuce, romaineraw	1/2 c   28	10	13	0.77
casaba melon	raw	1 cup 	170	9	12	0.75
strawberries	raw	1 cup	159	21	28	0.75
broccoli	raw	1/2 c   44	21	29	0.72
apricot		raw	3 me	106	15	21	0.71
dock		raw 	1/2 c   67	29	42	0.69
kiwifruit	raw	1 med	76	20	31	0.65
Brussels sproutsboiled	1/2 c	78	28	44	0.64
French beans	boiled	1 cup	177	111	181	0.61
cauliflower	raw	1/2 c   50	14	23	0.61
blueberries	raw	1 cup	145	9	15	0.60
carrots		raw	1 med	72	19	32	0.59
cantaloupe	raw	1 cup 	160	17	29	0.59
fruit cocktail	canned  1/2 c	128	8	14	0.57
squash, summer	raw	1/2 c   65	13	23	0.57
apple, w/o skin	raw	1 med	128	5	9	0.56
sweet potato	baked	1 med	114	32	62	0.52
raisins, seedlessraw	2/3 c	100	49	97	0.51
zucchini        raw	1/2 c   65	10	21	0.48
persimmon, Japaneseraw	1 med	168	13	28	0.46
tomato, green	raw	1 med	123	16	35	0.46
peach		raw	1 med   87	5	11	0.45
alfalfa sprouts	raw	1 cup	33	10	23	0.43
asparagus	boiled	1/2 c   90	22	54	0.41
beets		boiled	1/2 c	85	9	26	0.35
banana		raw	1 med	114	7	22	0.32
plum		raw	1 med	66	2	7	0.29
avocado, Fla	raw	1 med	304	33	119	0.28
tomato, red	raw	1 med	123	8	29	0.28
nectarine	raw	1 med	136	6	22	0.27
peppers, sweet	raw	1/2 c	50	3	11	0.27
avocado, Cal.   raw	1 med	173	19	73	0.26
peas, green	raw	1/2 c	78	19	84	0.23
lima beans	boiled	1 cup	188	52	231	0.23
kidney beans,redboiled	1 cup	177	50	252	0.20
potato (no skin)raw	1 med	112	8	52	0.15
mushrooms	raw	1/2 c   35	2	36	0.06
corn, yellow	boiled	1/2 c	82	2	84	0.02
Notice these Ornate box turtles are enjoying corn on the cob. Corn is very low in calcium and should not be giving regularly without calcium addition. But like all creatures, box turtles seem to really enjoy the foods that aren't good for them!



Common Conversions

1 kilogram (kg) = 2.2 pounds (lb)
2.2 pounds (lb) = 1000 grams (gm)
1 gram (g) = 1000 milligrams (mg)
1 lb = 454 g = .454 kg
1 lb = 16 ounces (oz)
1 cup (c) = 8 fl. oz = 16 tablespoons (tbsp)
1 oz = 30 milliliters (ml)
1 tbsp - 3 teaspoons (tsp) = 15 ml
1 tsp = 5 ml
1 liter (L) - 1000 ml
1 ml = 1 cubic centimeter (cc)
To convert centigrade to Fahrenheit: (C x 1.8) + 32 = F
To convert Fahrenheit to centigrade: (F - 32) x .555 = C


Go to next chapter, Health Care for Box Turtles.

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Disclaimer: Please use all information contained on this web site at your own risk. Last updated on December 30, 2010 .