12.1. INTRODUCTION

Sufficient and regular consumption of fruits and vegetables (FV) is commonly regarded as an essential nutritional, preventive activity to maintain health. A lot of scientific publications demonstrate that adequate consumption of plant foods is associated with a decreased risk of chronic degenerative diseases, such as coronary heart disease, stroke, diabetes or certain types of cancer (Bazzano et al., 2008; Dauchet et al., 2005, 2006; Iqbal et al., 2008; Joshipura et al., 1999; Ness and Powles, 1997; Nikolić et al., 2008; Nöthlings et al., 2008; Pomerleau et al., 2006; Steinmetz and Potter, 1996; Wright et al., 2008; Yamaji et al., 2008). The risk-reducing effects are attributed to bioactive components including phytochemicals, phytonutrients and vitamins, minerals and fibre (Brown et al., 1999; Dragsted et al., 2004; Herrera et al., 2009; Lampe, 1999).

Around the world, various Public Health Nutrition strategies such as ‘5 a day’ are applied to encourage people to increase consumption of FV. However, these have met with limited success: nutrition reports and surveys reveal that people consume about 300 g of FV per day (Billson et al., 1999; Casagrande et al., 2007; Elmadfa et al., 2008; German Ministry for Nutrition, Agriculture and Consumer Protection, 2011; Naska et al., 2000), far less than the recommended 400 g up to 650 g per day (Danish Veterinary and Food Administration, 1998; United States Department of Agriculture, 2010; WHO, Food and Agriculture Organization of the United Nations, 2003).

Many people rarely achieve the recommended intake of FV due to several reasons such as taste preferences, convenience, availability, difficult coordination with their working world, ignorance and so on. FV consumption before exercise training can also lead to digestive discomfort during exercise due to the high fructose and fibre content (Ivy and Portman, 2004; Lamprecht and Smekal, 2004). Inadequate FV intake in a person’s daily diet can lead to underconsumption of bioactive compounds. This situation provides a rationale for offering concentrated FV nutrition, especially for exercising people.

A well-balanced mixture of phytonutrients, vitamins, minerals and other bioactives from a variety of FV may lead to additive and synergistic interactions in human metabolism that result in health benefits (Liu, 2003; Oude Griep et al., 2010). Hence, to bring as many as possible of these FV bioactives together in one supplement might be superior to supplements containing only vitamins, phytochemicals, juice or powder from just one or a few fruits and/or vegetables.

This chapter refers to studies that used supplementation with mixed FV concentrates in relation to exercising people and their redox and immune system, independent of the training status. We address three questions:

• Can supplementation with mixed FV concentrates modulate redox homeostasis in exercising people?
• Can supplementation with mixed FV concentrates modulate the immune system of exercising people?
• How can sport nutrition advisors decide whether or not to supplement with mixed FV concentrates?

A search of Medline/PubMed and the Cochrane library returned six original articles—with only one FV concentrate (Juice Plus + ®, NSA LLC, Collierville, TN, USA)—that pertain to exercising people and their redox and immune systems.

12.2. CAN SUPPLEMENTATION WITH MIXED FRUIT AND VEGETABLE CONCENTRATES MODULATE REDOX HOMEOSTASIS IN EXERCISING PEOPLE?

Increased metabolism due to exercise training results in enhanced demands for energy, protein, carbohydrate, water, essential fatty acids and also micronutrients such as vitamins, phytonutrients and minerals. A deficit of micronutrients with redox functions can result in imbalanced redox biology in favour of accumulation of reactive oxygen and nitrogen species (RONS) and disturbed redox signalling and control. This situation is called oxidative stress, which results in molecular, cell and tissue damage (Chevion et al., 2003; Peternelj and Coombes, 2011; Petibois and Déléris, 2005; Urso and Clarkson, 2003). In physical exercise, an overwhelming production of RONS can occur which leads to increased inflammatory processes, decreased immunity, increased susceptibility to injury and prolonged recovery (Fischer et al., 2004; Kuipers, 1994; Peters et al., 1993; Saxton et al., 1994).

Scientific literature is scarce regarding exercising people with respect to supplementation with mixed FV concentrates, although a recent systematic review included research on healthy subjects, both trained and untrained (Esfahani et al., 2011). This review revealed that daily consumption of the commercially available encapsulated mixed fruit and vegetable concentrates increased serum concentrations of major antioxidant vitamins. Esfahani et al. (2011) also reported reduced concentrations of oxidative stress and inflammatory markers and promising health advantages on markers of immunity and endothelial function. They noted a diversity of studies with respect to design, study population and the variability in the measured outcomes and assays utilised.

12.2.1. Randomised Controlled Trials That Investigated Fruit and Vegetable Supplementation on Redox Homeostasis in Exercising People

Bloomer et al. (2006) reported that use of the three-blend fruit, vegetable and berry (FVB) form of this supplement resulted in reduced exercise-induced increase of plasma protein carbonyl concentrations—a marker of RONS induced protein oxidation—compared with placebo after 30 min treadmill running at 80% of VO_2max. Trained subjects had consumed the nutraceutical continuously for 2 weeks with their meals.

This group also conducted a gender comparison of exercise-induced oxidative stress (Goldfarb et al., 2007). They found that trained women had higher resting antioxidant levels (reduced glutathione, vitamin E) than their trained male counterparts. With FVB supplementation, plasma vitamin E differences disappeared. Markers of oxidative stress (protein carbonyls, oxidised glutathione, malondialdehyde) increased similarly in both genders in response to exercise of similar intensity and duration. The FVB supplementation attenuated the reduced glutathione (GSH) decrease, and the oxidised glutathione and protein carbonyls increased compared with the placebo group—with no gender differences. Also, plasma vitamin C increased with mixed FV supplementation compared with placebo. They concluded that 2 weeks of supplementation with the FVB concentrate can attenuate exercise-induced oxidative stress equally in both genders.

In a randomised, double-blinded, placebo-controlled trial in a cohort of trained men (Lamprecht et al., 2007), all non-smokers, we also demonstrated that daily supplementation for 28 weeks with the FVB capsules (with meals) reduced carbonyl proteins (CP). It is noteworthy that this group clearly demonstrated a non-adequate intake of FV: instead of >5 portions/day, they only consumed 2 portions/day.

With the same cohort of trained men, we also conducted endurance tests with distinct intensities: at 70% of VO_2max and at 80% of VO_2max (Lamprecht et al., 2009b). The 70% intensity was adjusted about 10% below the anaerobic threshold, and the second slightly above. At each intensity level, we tested both a placebo group and the active group, which received the encapsulated mixed FVB concentrate. We found that post-exercise CP concentrations increased significantly at 80% VO_2max intensity but not at 70%; only in the placebo group this phenomenon occurred at all measured time points (Table 12.1). Towards the end of the study (28 weeks), when individual stress profile was increased by 45% more hours on duty per week, CP concentrations approached 1 nmol/mg protein after 80% VO_2max intensity in the placebo group. Referring to our own laboratory data obtained from athletes during the past few years, CP concentrations close to 1 nmol/mg protein (based on our applied method, described in Lamprecht et al., 2009b) are related to increased events of common cold and inflammation (unpublished data).

TABLE 12.1

Differences between Long-Term FVB Supplementation and Placebo in Post-Exercise CP Concentrations of Stressed, Non-Smoking, Trained Men

In another randomised, double-blinded, placebo-controlled study, we investigated a cohort of obese women and assessed the effects of 8-week FBV supplementation and a single bout of controlled walking exercise on CP, tumour necrosis factor (TNF)-alpha, total oxidation status (TOS) and oxidised LDL (oxLDL) (Lamprecht et al., 2013). Evaluation of the women’s diet also revealed that they did not consume enough FV, just two portions per day. Following 8 weeks of supplementation compared with placebo, the FBV group had a significant reduction in CP, oxLDL, TOS and TNF-alpha. It is noteworthy that low-grade inflammation marker TNF-alpha was above the normal range at baseline and decreased to a physiological range after 8 weeks of mixed FVB supplementation. Thirty minutes of walking exercise at 70% of VO_2max did not show any significant influence on the measured biomarkers indicating that this kind of exercise does not induce oxidative stress and inflammation in obese women. Furthermore, this study demonstrates that obese middle-aged women with non-adequate FV intake can benefit from mixed FVB supplementation in respect of redox-balancing and attenuation of low-grade inflammation.

Additionally, it is important to mention that FVB supplementation showed neither pro-oxidant effects nor changes of antioxidant enzymes in our studies (Lamprecht et al., 2007, 2009b). This is in contradiction to some exercise studies, which have reported increased lipid peroxidation and decreased plasma glutathione peroxidase (GPx) in trained men after antioxidant supplementation (Knez et al., 2007; Lamprecht et al., 2009a; Nieman et al., 2004). A decrease of antioxidant enzyme GPx could cause a weakening of the body’s antioxidant system. This means that supplementation with antioxidants does not provide a net benefit when internal antioxidant systems are regulated down in parallel. Obviously, this down-regulation does not occur with adequate supplementation with mixed FVB concentrates, even after long-term supplementation of 7 months (Lamprecht et al., 2007).

Under the focus of resistance exercise, there is some evidence that antioxidant supplementation could offer protection from exercise-induced muscular and oxidative damage, inflammation, muscle force loss and fatigue (Bloomer et al., 2004; Bryer and Goldfarb, 2006; Nakhostin-Roohi et al., 2008; Palazzetti et al., 2004; Silva et al., 2010). If so, this would accelerate recovery, especially from resistance training, and consequently lead to increased strength performance. However, a number of studies suggest that antioxidant supplementation might promote muscle damage and hinder recovery (Avery et al., 2003; Childs et al., 2001; Close et al., 2006; Teixeira et al., 2009). These conflicting data are due to the diversity of study protocols with different methods, subjects, surrogate endpoints, outcome measures, products and so on.

Recently, Goldfarb et al. (2007) showed that 4-week supplementation with the mixed FVB juice concentrate (with meals) leads to significantly lesser increases in CP, MDA and oxidised glutathione (GSSG) after eccentric exercise in young people (18–35 years). Although the authors conducted diet analyses their paper did not reveal information about the subject’s fruit and vegetable intake. We might speculate that this was not different from other age-matched cohorts and thus too low. However, they found no differences between supplementation and placebo in the context of functional changes related to pain and muscle damage between their non-resistance trained study subjects.

To summarise, these six described publications reveal that

• Increased resting CP and TOS values at baseline are reduced significantly after FV supplementation, in groups with non-adequate FV intake
• Increased resting values of low-grade inflammation marker TNF-alpha in obese women: FVB supplementation can decrease it significantly
• After 8 weeks, FV supplementation can decrease oxLDL concentrations significantly in obese women with very low FV consumption
• With strenuous endurance exercise or eccentric exercise, the increase in CP, MDA and GSSG can be avoided by FVB supplementation
• FVB supplementation can attenuate exercise-induced GSH decrease
• Both genders respond similarly to the FVB supplementation
• Activity of erythrocyte antioxidant enzymes seems not to be affected

12.3. CAN SUPPLEMENTATION WITH MIXED FRUIT AND VEGETABLE CONCENTRATES MODULATE THE IMMUNE SYSTEM OF EXERCISING PEOPLE?

12.3.3. Dosage of Mixed Fruit and Vegetable Supplementation

High-dose supplementation with certain antioxidants can exert pro-oxidant effects, displace other important antioxidants or interfere with essential defence mechanisms, such as apoptosis, damage to essential lipids and competition for absorption of other essential compounds (Soni et al., 2010). In an exercise study, we demonstrated that supplementation with higher concentrations of vitamin E and β-carotene increased lipid peroxidation and decreased GPx in plasma. Several studies on clinical endpoints revealed that supplementation with vitamin E and/or beta-carotene can increase the risk of mortality, incidence and recurrence of cancers, and increased the risk for cardiovascular diseases (ATBC Cancer Prevention Study Group, 1994; Bairati et al., 2006; Belch et al., 2008; Cook et al., 2007; Lonn et al., 2005; Miller et al., 2005; Omenn et al., 1996). These studies suggest that >400 IU/day of vitamin E and ≥20 mg of β-carotene/day are rather detrimental and support the occurrence of the described outcomes.

Pro-oxidant and antioxidant roles have also been found for bioactive phytochemicals, such as flavonoids, naturally occurring phenolic compounds derived from plants. Flavonoids have been reported to inhibit lipid peroxidation, chelate metal ions, inactivate lipoxygenase, autoxidise and form high-reactive RONS, act in signal transduction and so on (Soni et al., 2010). Consumption of >20 mg of polyphenols per serving reduces iron absorption and could be an issue for populations with marginal iron status (Corcoran et al., 2012). Despite these data, it is commonly believed that in Western populations consuming adequate haem iron and ascorbic acid (which enhances non-haem iron absorption), the risk of developing anaemia due to dietary flavonoid intake is low.

The sole mixed FV concentrate (Juice Plus + , NSA LLC, Collierville, TN, USA) from which publications with randomised controlled trials can be found on PubMed/Medline contains different vitamins such as E, C and β-carotene as well as a variety of phytochemicals. From the composition of the product labelled on the packaging (<10 mg β-carotene/day and <100 IU/day of vitamin E) and the body of papers reporting beneficial clinical outcomes, we conclude that the daily recommended dosage for intake of this FV(B) supplement does not reach dosages of certain antioxidants as described above for detrimental outcomes, not even when applied in the long term. In addition, the investigator handbook of this product reveals that only 13 adverse events (like minor gastrointestinal complaints and hive-like rash) were reported in more than 25 clinical studies with almost 2000 subjects, which is far less than 1%.

Juice Plus+ is a low-dosed supplement which provides a variety of bioactives, including vitamins and phytochemicals. We speculate that this fact might contribute to the observed beneficial clinical outcomes.

To summarise, data from studies with FV and FVB supplementation indicate that people’s immunity can benefit when dietary consumption of FV is low and an increased psycho-physiological stress profile occurs.

Overdosing with the sole FV or the FVB concentrate reported on PubMed/Medline is not realistic as long as consumers contain themselves on dosage recommendations of 4–6 capsules/day.

Nevertheless, further research on FV(B) supplementation in relation to immunity and exercise—especially mechanistic studies and randomised clinical trials—is warranted to corroborate the existing data (Table 12.2).

TABLE 12.2

Summary of Sport Studies with Mixed FV or FVB Supplements

12.4. HOW CAN SPORT NUTRITION ADVISORS DECIDE WHETHER OR NOT TO SUPPLEMENT WITH MIXED FV CONCENTRATES?

To decide pro or con supplementation with mixed FV concentrates, at least five domains have to be considered. In a person’s life, at the time point of counselling, each domain has a certain manifestation: favourable or non-favourable. Table 12.3 depicts the five influencing domains with examples for pro and contra supplementation, respectively. We suggest terming these domains ‘diet’, ‘biochemical checkup’, ‘exercise/competition regimen’, ‘basic conditions’ and ‘product quality’:

TABLE 12.3

Overview and Examples for Non-Favourable or Favourable Manifestations of Each Influencing Domain

• 1. The person’s diet: food and fluid intake: A 7-day food record is necessary to estimate the basic diet and also daily plant food intake. A non-favourable characteristic of this domain indicates supplementation with FVB concentrates, for example, individual digestive situation or certain aversions/preferences do not allow dietary intake of 5 portions/day or more.
• 2. Biochemical check-up: Analysis of oxidative stress and inflammatory parameters in the blood and urine as well as a standard blood chemistry panel. With respect to the athlete’s clinical history, age, gender and genetics, it is useful to conduct a panel of several parameters at rest and post-exercise. FVB supplementation is a tool to combat excess oxidative stress or inflammation.
• 3. Exercise/competition regimen: In certain time periods, stabilisation of immunity and avoidance of inflammatory processes are of higher priority than adaptation. During this time, FVB supplementation is indicated. During macrocycles primarily focused on adaptation, it might be indicated to reduce or even avoid supplementation with mixed FVB concentrates.
• 4. Underlying ‘basic conditions’ in an athlete’s training period: Training in hot and humid weather, stay in higher regions, cold and dry climate, polluted air, unfavourable training facilities and so on. Also, stressful daily life, mentally/emotionally disturbed everyday life, job, family and so on fall into this domain and contribute to decide pro or con FVB supplementation.
• 5. Quality and evidence of the FVB supplement/product itself: If FVB supplementation is indicated, the product has to provide scientific evidence of bioefficacy and must fulfil all safety criteria. Well-described methodology, evaluated dosage, timing and investigated target groups are key factors necessary to decide to choose a product. Possible adverse effects and recommendations to avoid digestive problems should be published to give an opportunity for quick adjustment.

Each domain should be evaluated for advantageousness on the athlete’s health and performance as well as the ‘interaction’ between domains. In the event that one or more certain domains reveal non-favourable characteristics/manifestations, the likelihood of FVB supplementation increases (except for the FV product, see Table 12.3 and Figure 12.1).

FIGURE 12.1

A ‘decision path’ to ease decision pro or contra FV supplementation to athletes’ and sporty people’s diet. First, the product should be evaluated in respect of scientific evidence of its bioefficacy as well as safety and (more...)

If FVB supplementation is indicated, the product should be added to one or more meals, depending on the regimen being used from published scientific studies with that product.

The decision pro or con regarding FVB supplementation has to be reevaluated continuously. On the basis of the subject’s genetic profile, absorption rates, bioavailability, pharmacokinetics, bioactivity, etc. might be different among people and could lead to a different response, even to supplementation regimens with scientific evidence for efficacy. Thus, after 3–16 weeks, depending on the training macro-cycle and/or period of the specific type of sport, frequently conducted counselling sessions with check-ups comprising all influencing domains reflect the most professional handling with this issue.

Note: Supplements are no replacement for dietary fibre! Even if FVB supplementation is indicated, these supplements cannot substitute for the recommended daily fibre intake of 20–35 g (Marlett et al., 2002). The uptake of dietary plant foods should increase to at least 5 portions/day, especially in less strenuous training periods, as long as this amount and frequency of intake does not result in digestive problems.

12.5. CONCLUDING REMARKS

The main base to stabilise redox homeostasis and immunity is a mixed, balanced diet. Supplementation with mixed FVB concentrates is indicated if health stabilisation and avoidance of oxidative stress and inflammation have priority.

It is not realistic to provide general advice pro or con regarding supplementation with mixed FVB concentrates. Pro or con and also amount and dosage of supplementation underlie individual evaluation of each influencing domain in every single person. The manifestation(s) of the five domains, diet, biochemical analyses and clinical history, exercise training, basic conditions and the product itself, are crucial for decision-making. Thus, in practice, a counsellor’s decision pro or con FVB supplementation should be based on a systematic decision-making procedure. A ‘decision tree’ as provided in this chapter might guide in finding the right solution.

In future, the number of exercise studies with these promising nutraceuticals should increase. The results from research in this field should be combined with practical observations and documentary reports to achieve sustainable health and performance of sporty people.

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