Juice Calculator

Orange juice is the king of vitamin C among common juices, providing approximately 124 mg per 8-oz serving (138% of the adult daily value). Grapefruit juice is second at about 94 mg per 8 oz. Pineapple juice provides about 47 mg per 8 oz. Apple and grape juices are relatively poor sources of vitamin C unless it is added artificially. For maximum vitamin C, fresh-squeezed OJ is superior to pasteurized commercial juice, which loses some vitamin C during processing.

Purple/Concord grape juice contains many of the same polyphenol compounds found in red wine, including resveratrol and quercetin, which are associated with cardiovascular benefits. Research has shown that regular consumption of 100% purple grape juice can modestly improve blood vessel function, reduce LDL oxidation, and lower blood pressure. While the antioxidant concentration is slightly lower than red wine, grape juice provides these benefits without the risks associated with alcohol consumption.

Some evidence supports cranberry juice as a preventive measure against urinary tract infections (UTIs), particularly in women with recurrent UTIs. Cranberry contains proanthocyanidins (PACs) that may prevent E. coli bacteria from adhering to urinary tract walls. However, the evidence is mixed — some meta-analyses show modest benefit while others show no significant effect. Cranberry juice does not treat existing UTIs, only potentially prevents recurrence. Note that commercial cranberry cocktail (not 100% juice) may have too little PAC content to be effective.

Grapefruit juice contains furanocoumarins that inhibit cytochrome P450 3A4 (CYP3A4), an enzyme that metabolizes many medications. This inhibition can increase blood levels of affected drugs to potentially dangerous levels. Medications affected include some statins (simvastatin, lovastatin), calcium channel blockers, immunosuppressants, certain antiretrovirals, and many others. If you take any prescription medication, check with your pharmacist or doctor before regularly consuming grapefruit juice. Even a single glass can have significant effects lasting 24 hours or more.

100% juice contains only fruit juice with no added sugar or water. Juice nectar is a mixture of juice (typically 25-50%), water, and usually added sweeteners — common with thick fruits like peach, pear, and mango. Juice cocktail or juice drink contains only a small percentage of actual juice (often 10-30%) mixed with water, high-fructose corn syrup or sugar, and flavorings. Always read labels: look for 100% juice on the label and check the ingredient list to ensure sugar is not one of the first ingredients.

Fresh-squeezed juice contains higher levels of vitamin C, enzymes, and aromatic flavor compounds that degrade during commercial processing and storage. Pasteurization (heat treatment) kills pathogens and extends shelf life but reduces heat-sensitive nutrients and volatile flavor compounds. However, commercial 100% juice is still a nutritious product. The most important distinction is between 100% juice (fresh or commercial) versus juice drinks/cocktails that contain substantial amounts of added sugar.

The American Academy of Pediatrics (AAP) recommends: no juice for infants under 12 months; 4 oz maximum per day for toddlers 1-3 years; 4-6 oz maximum per day for children 4-6 years; 8 oz maximum per day for children 7-18 years. These guidelines apply to 100% fruit juice. Juice should never be given in bottles or sippy cups that allow continuous sipping, as this promotes tooth decay. Whole fruit is always preferable to juice as it provides fiber and generally lower sugar density.

According to the USDA Dietary Guidelines, 1/2 cup (4 oz) of 100% fruit juice counts as 1/2 cup equivalent of fruit from the fruit group. However, the guidelines note that most fruit servings should come from whole fruits rather than juice, as whole fruits provide dietary fiber that juice lacks. Juice can count toward your daily fruit intake but should not be the primary way you meet fruit recommendations.

The glycemic index (GI) of most fruit juices is moderate to high: apple juice GI ≈ 40-50, orange juice GI ≈ 50-55, grape juice GI ≈ 52, pineapple juice GI ≈ 46, cranberry juice GI ≈ 52-58, grapefruit juice GI ≈ 48. These values are generally lower than pure glucose (GI 100) or sugar (GI 65) but higher than whole fruit due to absent fiber. The glycemic load (which accounts for serving size) makes a standard 8-oz glass of juice a moderate to high glycemic load food.