Prunes

Prunes, known for their deep and shriveled skin, are actually a dried version of the plum. Per half-cup serving, prunes contain about 6 grams of dietary fiber—which our bodies rely on for healthy bowel movements. To put that in perspective: The National Academy of Medicine recommends women consume about 25 grams of dietary fiber a day, and men, 38 grams daily.

There are other properties that make prunes exceptional in relieving constipation. Fructose and sorbitol, sugars and sugar alcohols found in the fruit, often produce a laxative-like effect on digestion, making it a bit easier to go.

Because of their sweet flavor and well-known mild laxative effect, prunes are considered to be an epitome of functional foods, but the understanding of their mode of action is still unclear. Dried prunes contain approximately 6.1 g of dietary fiber per 100 g, while prune juice is devoid of fiber due to filtration before bottling. The laxative action of both prune and prune juice could be explained by their high sorbitol content (14.7 and 6.1 g/100 g, respectively). Prunes are good source of energy in the form of simple sugars, but do not mediate a rapid rise in blood sugar concentration, possibly because of high fiber, fructose, and sorbitol content. Prunes contain large amounts of phenolic compounds (184 mg/100 g), mainly as neochlorogenic and chlorogenic acids, which may aid in the laxative action and delay glucose absorption. Phenolic compounds in prunes had been found to inhibit human LDL oxidation in vitro, and thus might serve as preventive agents against chronic diseases, such as heart disease and cancer. 

Additionally, high potassium content of prunes (745 mg/100 g) might be beneficial for cardiovascular health. Dried prunes are an important source of boron, which is postulated to play a role in prevention of osteoporosis. A serving of prunes (100 g) fulfills the daily requirement for boron (2 to 3 mg). 

Chia Seeds

Another super-seed, chia seeds (yes, they're the very same ones used to grow Chia Pets) are especially rich in plant omega-3 fats, like the more popular flaxseeds. 

And ounce for ounce, chia seeds contain more fiber and calcium than flax. You can pick up a bag in health-food stores or order them online. Use chia seeds just as you would other seeds or chopped nuts; try them sprinkled on oatmeal, cereal, yogurt, or cottage cheese, or mixed into dips or salad dressings. Unlike with flax, you don't need to grind them first because they're completely digestible in whole form. Consider adding chia seeds to pancakes, muffins, and other baked goods too. Mixed with water, they make a great vegan egg substitute.

more on chia seeds; chia pudding recipe

Best place to buy:      $37.56   Bob's Red Mill Chia Seed, 16 oz (Pack of 4)

Cranberries

Cranberries are well known for their ability to cure urinary tract infections (UTIs). In fact, recent research has shown that proanthocyanidins (PACs) are the main factor that helps eliminate UTIs via a mechanism that promotes bacterial anti-adhesion. 

The PACs essentially act as a barrier to bacteria that normally latch onto the urinary tract lining, and thus prevent accumulation of the bacteria that cause UTIs, and flush them out.

Cranberries also have beneficial anti-cancer effects, having been shown to inhibit the growth of several cancer cell lines, including breast cancer cells. Cranberry phytochemical extracts resulted in a 25% higher ratio of apoptotic breast cancer cell death as compared to control groups without cranberry supplementation. The phytochemical extracts of cranberries suppressed growth likely due to the initiation of apoptosis and G1 cycle arrest. They also protect against human oral, colon, and prostate cancer cell lines.

Cranberries are also great for the heart – studies have shown that in patients with coronary artery disease, consumption of cranberry juice helped reduce carotid femoral pulse wave velocity (a clinically relevant measure of arterial stiffness). In addition, cranberries improve liver health due to their high vitamin C content. Vitamin C helps trigger production of glutathione in the liver, a key antioxidant needed for detoxification. Glutathione binds heavy metals and drugs in the bloodstream and makes it easier for the liver to cleanse your blood of these substances.

Cranberries and kidney stones

Cranberries, especially concentrated cranberry extracts, may contain high levels of oxalate and are considered to be a risk factor for kidney stones when consumed in high amounts.