By Steven Cortez
Even though humans cannot synthesize vitamin C, every tissue and cell in our body needs this nutrient for healthy growth and repair.1,2
Maintaining optimal levels of vitamin C is difficult because it is water soluble and cannot be stored in the body.3 This inability to maintain high vitamin C levels is recognized by researchers as limiting its potential benefit, especially with regard to chronic illness.4
For years, scientists have been looking for ways to boost the impact of each dose of vitamin C. Fortunately, a method has been discovered to increase the speed at which vitamin C is absorbed.5 Reaching peak concentrations faster offers the edge your body needs to optimize its exposure to vitamin C following each dose.
Maximizing Your Vitamin C
Two botanical compounds, piperine and dihydroquercetin can improve your body’s utilization of vitamin C.5-7
Piperine, a unique alkaloid found in black pepper, has been shown to significantly speed up vitamin C’s absorption into the bloodstream.5
Piperine has also been shown to increase absorption of various nutrients such as curcumin by favorably altering the characteristics of the cells lining the digestive tract.8 Studies on animals and in the lab demonstrate that piperine, administered orally, boosts cellular levels of vitamin C, especially in animals undergoing excessive oxidative stress, such as those with cancer.9,10 Higher levels appear to be the result of faster absorption, the characteristic effect of piperine.
In a human clinical study, a piperine-containing oral vitamin C supplement was superior to another “enhanced” vitamin C formulation, speeding the time to peak plasma concentrations of the vitamin. This resulted in a slight but important increase in the total exposure of subjects’ bodies to vitamin C in the first 4 hours following ingestion. At 30, 60, and even at 90 minutes post-ingestion, subjects taking the piperine-enhanced formulation had significantly higher plasma vitamin C than did subjects taking the other formulation.5
By shortening the time from ingestion to peak levels, the body can reap the benefits of a given dose of vitamin C for a longer time. Given the importance of vitamin C in thousands of biochemical reactions, this apparently slight advantage may make a large difference in health outcomes.
Dihydroquercetin is a potent flavonoid molecule found in grape leaf extracts.11 It optimizes vitamin C through a mechanism of action entirely different from piperine. Like all antioxidants, vitamin C is “used up” in the process of scavenging toxic reactive oxygen and nitrogen species.12 In scientific terms, active vitamin C “reduces” oxidant molecules by donating electrons, thereby becoming oxidized (and hence, inactive) itself.
Dihydroquercetin has been shown to donate electrons back to these oxidized vitamin C molecules, essentially making them brand new and regenerating their ability to combat oxidant damage in cells and plasma.7 When tested against other protective nutrients, only dihydroquercetin was capable of providing this vitamin C-regenerative effect.7
The dual effects on vitamin C of piperine (speeding absorption) and dihydroquercetin (speeding renewal) add up to a novel formulation that reaches peak plasma levels faster to keep cellular levels optimized longer.5 This represents a new “harder working” form of vitamin C.
Let’s now examine the potential impact of such optimization by reviewing the latest on vitamin C’s expanding role in health promotion.
Oxidative damage plays a central role in development of heart disease and strokes, as oxidized low-density lipoproteins (LDL) accumulate and trigger inflammatory reactions within blood vessel walls.13 Oxidation impairs endothelial function, the measure of blood vessels’ ability to regulate blood flow and pressure, potentially starving vital tissues (such as hard-working heart muscle) of their essential blood supply.14 Aging and chronic diseases such as diabetes bring on even more oxidation and loss of normal blood vessel function.14,15
Epidemiological studies demonstrate that people with the highest blood levels and daily intakes of vitamin C are at as much as a 50% reduced risk of developing or dying from cardiovascular diseases.16-23 Men with the lowest blood levels of vitamin C have a 2.4-fold greater risk of having a stroke compared with those having the highest levels of vitamin C. That risk is enhanced in men who had additional risk factors such as being overweight or hypertensive.24 And the risk of having high blood pressure in the first place is 22% lower in people with the highest vitamin C intake, compared with those having the lowest.25
One study found that people who took more than 700 mg/day of supplemental vitamin C had a 25% lower chance of developing coronary heart disease, the precursor of a heart attack.26
Studies of vitamin C administration directly into veins or arteries in human volunteers and people with arterial disease reveal a powerful effect on endothelial function, demonstrating immediate and significant improvements in blood flow and blood pressure.27-30 And studies of oral vitamin C supplementation at doses of 1,000 mg/day provide evidence of reduced oxidative damage to LDL cholesterol in diabetics, a group at very high risk for cardiovascular complications.31 A study of older adults, published in late 2012, showed a substantial and significant improvement in endothelial function following an oral dose of vitamin C, 1,000 mg, coupled with vitamin E and alpha-lipoic acid, two other natural antioxidants.15 Since it is difficult to maintain all-day optimal vitamin C blood levels, boosting the body’s absorption of vitamin C and reducing its degradation, as seen with piperine and dihydroquercetin, has intriguing therapeutic potential.
Cancer results from the mutation of genes that regulate cellular proliferation. Some of this DNA gene damage is caused by excess oxidation. Some studies suggest that 1 in 12 cancers might be prevented by assuring higher levels of antioxidant intake.32
And indeed, some studies show that those with the highest overall antioxidant vitamin intake are protected against many forms of cancer.
The best evidence for supplementation as a cancer preventive is found in cancers of the digestive tract. Vitamin C can prevent stomach colonization with the bacterium H. pylori, a major cause of stomach and small intestinal cancers.33 It does so, in part, by blocking an oxidant-induced enzyme the organism needs in order to set up shop in the stomach lining.33
Studies of supplementation with vitamin C, in combination with other antioxidant vitamins and minerals, demonstrate prevention of recurrent intestinal polyps (adenomas), the precursors of serious colorectal cancers.34,35 Similar findings have now been reported for esophageal cancer as well.36
There’s now evidence for a vitamin C protective effect in epidemiological and lab studies of breast cancer.37-39 One study showed that women who supplemented with vitamin C for more than ten years had a 42% reduced risk of developing breast cancer.38 And higher vitamin C intake produced a 65% reduction in risk of cancer of the cervix.40 Even pancreatic cancer, one of the deadliest malignancies known, was shown to be 33% less likely in those with higher blood levels of vitamin C.32
Again, dose and bioavailability of the vitamin seem to be critical; studies of vitamin C at 500 mg/day and lower tend not to demonstrate a significant protective effect.41 Furthermore, continued supplementation is a necessity; in one large clinical trial, supplementation with antioxidant vitamins including C decreased total cancer incidence and death rates, but that benefit disappeared within 5 years of stopping supplementation.42
High dose intravenous vitamin C has convincingly been shown to reduce markers of inflammation in cancer patients; we know that inflammation is critical to sustaining cancer cell reproduction and tumor growth.43 If we are to realize these benefits, we need to find ways to get the most out of our oral dosing, a goal that may be obtained through strategies like combining vitamin C with dihydroquercetin and piperine.
One important note: While vitamin C has been shown to be a valuable adjunct to conventional cancer treatment, the antioxidant power of vitamin C is so strong that it may have the potential to interfere with certain types of chemo- and radiation therapy, both of which can rely on producing free radicals to kill malignant cells.44 Due to the sensitive nature of radio- and chemotherapy administration, those who are currently undergoing chemo- or radiation therapy for a known cancer should speak with their treating oncologist regarding the best regimen and dosing of vitamin C for their individual situation.
The epidemics of obesity and type II diabetes have so much in common that they can be referred to as a single entity, diabesity. Oxidative stress is one of the central features of diabesity, being imposed by both excessive fat stores and by chronically elevated (or even borderline) blood sugar levels.45 Once tissue damage caused by glucose (glycation reactions) has taken place, there’s yet more oxidative stress. Together these factors account for most of the complications of diabesity, including poor cardiovascular outcomes, kidney disease, and nerve damage.
There’s been keen interest in the use of antioxidant vitamins to prevent diabesity’s complications. Studies with high-dose intravenous vitamin C show an immediate and marked reduction in aortic stiffness and central blood pressure during periods of acutely elevated glucose in human volunteers.46 That’s further confirmation of the idea that reliable tissue delivery of vitamin C has protective effects.
Additional evidence for vitamin C’s benefits in diabesity comes from supplementation studies demonstrating a reduction in markers of oxidative stress in obese adults, accompanied by favorable elevations in adiponectin, a protective fat-derived signaling molecule.31,47,48 And vitamin C, 1,000 mg/day plus vitamin E, 800 IU/day, significantly reduced the after-meal memory impairment that’s so common in type II diabetes, indicating that oxidative stress is involved in producing that phenomenon.49
Of course, the central concern for those with diabesity is getting control of their blood sugar. Studies show that vitamin C improves insulin sensitivity as a result of its antioxidant effects.50 The combination of vitamin C with vitamin E produces a further improvement, increasing glucose utilization without creating oxidizing byproducts.48,50 A further benefit of the combination is a reduction in a host of adhesion molecules that increase likelihood of blocked arteries.48
Vitamin C has been the subject of endless controversy regarding its ability to prevent the common cold. Strong evidence now supports the observation that doses of about 1,000 mg/day, taken regularly, can shorten the duration of a cold.51,52
But the beneficial effects of vitamin C go much beyond the common cold. Immune system cells of almost every variety are able to concentrate vitamin C from the blood (so long as ample vitamin C is available).52,53 Cells in the immune system fight infections in part by destroying invading organisms with bursts of oxidative activity, but that puts adjacent healthy tissue at risk.54 Supplementation with bioavailable vitamin C protects normal host tissues, allowing the infecting organism to be destroyed without collateral damage.51,54
These immune-boosting functions have a clear effect on another major health concern, stomach infection with Helicobacter pylori, a major cause of gastritis and stomach cancer. Studies show that following eradication of the organism by antibiotics, sustained daily vitamin C supplements (500 to 1,000 mg/day) reduce the severity of stomach irritation and inflammation, and may help to prevent progression to stomach cancer.36,55-57
Lung tissue naturally bears the brunt of the continuous oxidant assault on the body. When oxidant damage triggers inflammation (and vice versa) in the lungs, a protective reflex called bronchospasm occurs, which we experience as asthma or chronic obstructive pulmonary disease (COPD).58
Studies show that vitamin C levels are lower in asthmatic patients, the result of excessive degradation of the vitamin as it battles oxidant damage.59 High intakes of vitamin C are associated with improved lung function and a delay in the deterioration that could lead to chronic obstructive pulmonary disease.60 Asthmatic patients challenged with drugs that can trigger bronchospasm respond less severely if they are pre-treated with antioxidant vitamins C and E.61 And vitamin C supplementation at 1,500 mg/day has been shown to attenuate the severity of exercise-induced asthma attacks in patients with known asthma.62
Bones require a strong matrix of collagen proteins in order to develop and maintain their structural integrity and proper mineralization.63 Vitamin C is essential for collagen production, and epidemiologic studies link poor vitamin C intake with bone loss.63,64 Animal studies reveal that vitamin C supplementation prevents post-menopausal bone loss by stimulating new bone formation.64
Human studies suggest that vitamin C reduces rates of bone resorption, the principle cause of osteoporosis.65 In older men and postmenopausal women, higher vitamin C intake is associated with lower long-term bone loss.63,66 This leads directly to a reduction in the risk of hip and other non-vertebral fractures in people with the highest vitamin C intake.67
Supplementation with 1,000 mg/day of vitamin C has now been convincingly demonstrated to prevent oxidant-induced bone loss in elderly people.66
Vitamin C is gaining ever-greater attention for its potential to reduce the impact of chronic, age-related diseases. Yet the modest doses found in conventional multi-vitamin formulas have not demonstrated protective effects.
Vitamin C’s levels in the blood are under tight control, making it difficult to achieve optimal levels, even with very large oral supplement doses. That tight control arises from three basic mechanisms: control of absorption, control of excretion, and control of vitamin C degradation in the tissues.
Enhancing some or all of these mechanisms may allow us to push vitamin C blood levels higher than previously thought attainable.
The nutrients piperine and dihydroquercetin, acting by different mechanisms, offer just such an opportunity: piperine for optimizing vitamin C uptake and dihydroquercetin for sustaining its activity.
And enhanced bioavailability is desirable, in light of vitamin C’s many known beneficial properties. Studies demonstrate that the proper dose of vitamin C supplementation can reduce cardiovascular risks, lower the threat of cancer, mitigate diabesity, boost immune function, improve lung function, and even prevent bone loss in osteoporosis. Imagine the added benefits that even a modest increase in the vitamin’s serum profile could provide.
Image from office.microsoft.com Clip Art and Image Library
Related Products and Information