Many foods are more acid-forming than acid-alkaline formulas indicate.

Foods contain substances impacting the acid-base balance. The Western diet is often viewed as being overly acid due to its high-level of animal-based protein and low-level of vegetable intake. Meanwhile, with ageing the ability to excrete acid compounds is reduced as kidney function declines and so there is a risk of acid retention and subsequent interstitial acidosis. Two systems used for calculating the Dietary Acid Load (DAL): the potential acid load of foods (PRAL) and the net endogenous acid production (NEAP). This report outlines weaknesses in these formulas and concludes that dietitians and nutritionists lack the necessary tools to research the acid-base hypothesis. Additionally, the report emphasizes the importance of food selection in the ageing population. Background: Foods contain substances impacting the acid-base balance. The Western diet is often viewed as being overly acid due to its high-level of animal-based protein and low-level of vegetable intake. There are concerns that the disproportionate acid intake promotes low-grade metabolic acidosis in the interstitial fluid, interstitial acidosis, and may lead to chronic disease. Two formulas are used for calculating the DAL: the PRAL and the NEAP. Both PRAL and NEAP are based on levels of protein and minerals. Aim: To identify additional food constituents that impact DAL. Methods: Review of the literature concerning the acid-forming and alkaline-forming constituents of foods. Results: Five additional food constituents were identified as potentially having a meaningful impact on DAL. The oxidation of taurine and the metabolism of fructose and purines increase acidity, whereas organic acids increase alkalinity. Additionally, polyphenols affect the microbiota which break down uric acid excreted in the intestinal tract. Conclusions: Neither PRAL nor NEAP provides complete assessments of the impact of foods on DAL. These formulas could be improved by the inclusion of dietary amino acids rather than protein, taurine, purines, fructose, organic acids and polyphenols. Currently, dietitians and nutritionists lack the necessary tools both to research the acid-base hypothesis and recommend managed diets. Managed diets are of particular importance for the elderly because of their reduced kidney function which increases the risk of acid retention and subsequent interstitial acidosis.

Curcumin/Turmeric: Their Effect on Serum Uric Acid Remains Unknown.

Various studies have investigated whether turmeric, or isolated curcumin, affects serum levels of uric acid. However, some studies have been hampered by problems in reliably measuring serum uric acid. For example, in one trial lasting 8 weeks, serum uric acid levels decreased (p < 0.01) for the control group, while in another 8-week trial serum uric acid levels increased (p < 0.01) for the control group.

Neural Transmission from Oropharyngeal Bitter Receptors to the Medulla is Partially or Completely Labelled-Line.

The ground breaking advances in taste cell receptor cell physiology over the last 20 years have established a functional basis which enables neural pathways to be mapped. There is.only one, or perhaps several, types of taste receptors for salt, sour, sweet and umami (meaty) tastes and stimulation of each receptor type elicits responses in different cognitive regions. These findings support the labelled-line neural pathway model. In contrast, there are 25 types of the bitter taste receptors which all produce the same cognitive sensation, a finding which supports the across-fiber pattern model. This paper compiles the findings.of several human studies investigating the impact of bitter tastants on postprandial hemodynamics, to demonstrate that diverse bitter tastants are capable of eliciting a range of characteristic reflex cephalic phase responses in the autonomic and cardiovascular systems. These findings indicate that neural pathways from the oropharyngeal bitter taste receptors to the nucleus of the solitary tract are either partially or completely labelled-line. Consequently, the hedonics of a bitter tastant are not an accurate indicator of the cephalic phase responses elicited by the tastant. The finding that secondary metabolites present in dietary condiments modulate autonomic activity and in particular postprandial hemodynamics is novel and adds a new dimension to our understanding of the ways in which humans are influenced by their diet, both in health and disease. These findings suggest that condiments play a role in food digestion, unrelated to their. hedonistic qualities. Consequently, condiments may be of significance to those with digestive disorders and especially for diabetics experiencing gastroparesis and/or postprandial hypotension. Additionally, the findings suggest a noninvasive method to assess the integrity of multiple neural pathways. For investigators exploring the effect of condiments on autonomic reflexes, traditional cuisines may be a valuable source as they are full of uncharted human recordings.

Bitters: Time for a New Paradigm.

In plant-based medical systems, bitter tasting plants play a key role in managing dyspepsia. Yet when it comes to defining their mechanism of activity, herbalists and pharmacologists are split between two theories: one involves cephalic elicited vagal responses while the other comprises purely local responses. Recent studies indicate that bitters elicit a range of cephalic responses which alter postprandial gastric phase haemodynamics. Caffeine and regular coffee (Coffea arabica semen, L.) increase heart rate whereas gentian (Gentiana lutea radix, L.) and wormwood (Artemisia absinthium herba L.) increase tonus in the vascular resistance vessels. Following meals increased cardiac activity acts to support postprandial hyperaemia and maintain systemic blood pressure. The increased vascular tonus acts in parallel with the increased cardiac activity and in normal adults this additional pressor effect results in a reduced cardiac workload. The vascular response is a sympathetic reflex, evident after 5 minutes and dose dependent. Thus gentian and wormwood elicit cephalic responses which facilitate rather than stimulate digestive activity when postprandial hyperaemia is inadequate. Encapsulated caffeine elicits cardiovascular responses indicating that gastrointestinal bitter receptors are functionally active in humans. However, neither encapsulated gentian nor wormwood elicited cardiovascular responses during the gastric phase. These findings provide the platform for a new evidence-based paradigm.

Devil's Claw to suppress appetite--ghrelin receptor modulation potential of a Harpagophytum procumbens root extract.

Ghrelin is a stomach-derived peptide that has been identified as the only circulating hunger hormone that exerts a potent orexigenic effect via activation of its receptor, the growth hormone secretagogue receptor (GHS-R1a). Hence, the ghrelinergic system represents a promising target to treat obesity and obesity-related diseases. In this study we analysed the GHS-R1a receptor activating potential of Harpagophytum procumbens, popularly known as Devil's Claw, and its effect on food intake in vivo. H. procumbens is an important traditional medicinal plant from Southern Africa with potent anti-inflammatory and analgesic effects. This plant has been also used as an appetite modulator but most evidences are anecdotal and to our knowledge, no clear scientific studies relating to appetite modulation have been done to this date. The ghrelin receptor activation potential of an extract derived from the dried tuberous roots of H. procumbens was analysed by calcium mobilization and receptor internalization assays in human embryonic kidney cells (Hek) stably expressing the GHS-R1a receptor. Food intake was investigated in male C57BL/6 mice following intraperitoneal administration of H. procumbens root extract in ad libitum and food restricted conditions. Exposure to H. procumbens extract demonstrated a significant increased cellular calcium influx but did not induce subsequent GHS-R1a receptor internalization, which is a characteristic for full receptor activation. A significant anorexigenic effect was observed in male C57BL/6 mice following peripheral administration of H. procumbens extract. We conclude that H. procumbens root extract is a potential novel source for potent anti-obesity bioactives. These results reinforce the promising potential of natural bioactives to be developed into functional foods with weight-loss and weight maintenance benefits.

Bitter tastants alter gastric-phase postprandial haemodynamics.

ETHNOPHARMACOLOGICAL RELEVANCE: Since Greco-Roman times bitter tastants have been used in Europe to treat digestive disorders, yet no pharmacological mechanism has been identified which can account for this practice. This study investigates whether the bitter tastants, gentian root (Gentian lutea L.) and wormwood herb (Artemisia absinthium L.), stimulate cephalic and/or gut receptors to alter postprandial haemodynamics during the gastric-phase of digestion. MATERIALS AND METHODS: Normal participants ingested (1) 100 mL water plus capsules containing either cellulose (placebo-control) or 1000 mg of each tastant (n=14); or (2) 100mL of water flavoured with 500 or 1500 mg of each tastant (a) gentian (n=12) and (b) wormwood (n=12). A single beat-to-beat cardiovascular recording was obtained for the entire session. Pre/post-ingestion contrasts with the control were analysed for (1) the encapsulated tastants, in the "10 to 15" minute post-ingestion period, and (2) the flavoured water in the "5 to 10" minute post-ingestion period. RESULTS: Water, the placebo-control, increased cardiac contraction force and blood pressure notwithstanding heart rate decreases. Encapsulated tastants did not further alter postprandial haemodynamics. In contrast gentian (500 and 1500 mg) and wormwood (1500 mg) flavoured water elicited increased peripheral vascular resistance and decreased cardiac output, primarily by reducing stroke volume rather than heart rate. CONCLUSIONS: Drinking 100mL water elicits a pressor effect during the gastric-phase of digestion due to increased cardiac contraction force. The addition of bitter tastants to water elicits an additional and parallel pressor effect due to increased peripheral vascular resistance; yet the extent of the post-prandial blood pressure increases are unchanged, presumably due to baroreflex buffering. The vascular response elicited by bitter tastants can be categorised as a sympathetically-mediated cephalic-phase response. A possible mechanism by which bitter tastants could positively influence digestion is altering gastric-phase postprandial haemodynamics and supporting postprandial hyperaemia.

Caffeine in hot drinks elicits cephalic phase responses involving cardiac activity.

Caffeine stimulates both oropharyngeal and gut bitter taste receptors (hTAS2Rs) and so has the potential to elicit reflex autonomic responses. Coffee containing 130 mg caffeine has been reported to increase heart rate for 30 min post-ingestion. Whereas added-caffeine, in doses of 25 to 200 mg, ingested with decaffeinated coffee/tea decreases heart rate 10 to 30 min post-ingestion. This study aimed to clarify caffeine's chemosensory impact. Double-espresso coffees were compared to a placebo-control capsule in a double-blind between-measures design. Coffees tested were regular coffee (130 mg caffeine) and decaffeinated coffee with added-caffeine (0, 67 and 134 mg). Cardiovascular measures from three post-ingestion phases: 1) 0 to 5; 2) 10 to 15; and 3) 25 to 30 min; were compared to pre-ingestion measures. Participants comprised 11 women in the control group and 10 women in the test group. Decaffeinated coffee elicited no changes. Decaffeinated coffee with 67 mg caffeine: decreased dp/dt in Phase 1. Decaffeinated coffee with 134 mg caffeine: increased heart rate in Phases 1 and 2; decreased spontaneous baroreflex sensitivity in Phase 1; and increased diastolic pressure in Phases 2 and 3. Regular coffee: increased heart rate in Phases 1 and 2; decreased dp/dt in all phases; and decreased systolic pressure in Phase 1. Caffeine is the substance in regular coffee which elicits chemosensory autonomic reflex responses, which involves heart activity and the baroreflex. Compared to the caffeine in regular coffee, added-caffeine elicits somewhat different chemosensory responses including a more pronounced pressor effect and resetting of the baroreflex. Caffeine in commonly consumed amounts, as well as modulating body processes by blocking adenosine receptors, can elicit reflex autonomic responses during the ingestion of caffeinated drinks. It is plausible that caffeine stimulates hTAS2Rs, during the ingestion of coffee, eliciting cephalic phase responses. These cephalic phase responses likely result from vagal withdrawal and it is uncertain whether they enhance digestion or not.

Respiratory and non-respiratory sinus arrhythmia: implications for heart rate variability.

The quantity of blood arriving at the left side of the heart oscillates throughout the breathing cycle due to the mechanics of breathing. Neurally regulated fluctuations in the length of the heart period act to dampen oscillations of the left ventricular stroke volume entering the aorta. We have reported that stroke volume oscillations but not spectral frequency variability stroke volume measures can be used to estimate the breathing frequency. This study investigated with the same recordings whether heart period oscillations or spectral heart rate variability measures could function as estimators of breathing frequency. Continuous 270 s cardiovascular recordings were obtained from 22 healthy adult volunteers in the supine and upright postures. Breathing was recorded simultaneously. Breathing frequency and heart period oscillation frequency were calculated manually, while heart rate variability spectral maximums were obtained using heart rate variability software. These estimates were compared to the breathing frequency using the Bland-Altman agreement procedure. Estimates were required to be < ±10% (95% levels of agreement). The 95% levels of agreement measures for the heart period oscillation frequency (supine: -27.7 to 52.0%, upright: -37.8 to 45.9%) and the heart rate variability spectral maximum estimates (supine: -48.7 to 26.5% and -56.4 to 62.7%, upright: -37.8 to 39.3%) exceeded 10%. Multiple heart period oscillations were observed to occur during breathing cycles. Both respiratory and non-respiratory sinus arrhythmia was observed amongst healthy adults. This observation at least partly explains why heart period parameters and heart rate variability parameters are not reliable estimators of breathing frequency. In determining the validity of spectral heart rate variability measurements we suggest that it is the position of the spectral peaks and not the breathing frequency that should be the basis of decision making.

The immediate and short-term chemosensory impacts of coffee and caffeine on cardiovascular activity.

UNLABELLED: The immediate and short-term chemosensory impacts of coffee and caffeine on cardiovascular activity. INTRODUCTION: Caffeine is detected by 5 of the 25 gustatory bitter taste receptors (hTAS2Rs) as well as by intestinal STC-1 cell lines. Thus there is a possibility that caffeine may elicit reflex autonomic responses via chemosensory stimulation. METHODS: The cardiovascular impacts of double-espresso coffee, regular (130 mg caffeine) and decaffeinated, and encapsulated caffeine (134 mg) were compared with a placebo-control capsule. Measures of four post-ingestion phases were extracted from a continuous recording of cardiovascular parameters and contrasted with pre-ingestion measures. Participants (12 women) were seated in all but the last phase when they were standing. RESULTS: Both coffees increased heart rate immediately after ingestion by decreasing both the diastolic interval and ejection time. The increases in heart rate following the ingestion of regular coffee extended for 30 min. Encapsulated caffeine decreased arterial compliance and increased diastolic pressure when present in the gut and later in the standing posture. DISCUSSION: These divergent findings indicate that during ingestion the caffeine in coffee can elicit autonomic arousal via the chemosensory stimulation of the gustatory receptors which extends for at least 30 min. In contrast, encapsulated caffeine can stimulate gastrointestinal receptors and elicit vascular responses involving digestion. CONCLUSION: Research findings on caffeine are not directly applicable to coffee and vice versa. The increase of heart rate resulting from coffee drinking is a plausible pharmacological explanation for the observation that coffee increases risk for coronary heart disease in the hour after ingestion.

Habitual coffee and tea drinkers experienced increases in blood pressure after consuming low to moderate doses of caffeine; these increases were larger upright than in the supine posture.

Caffeine users have been encouraged to consume caffeine regularly to maintain their caffeine tolerance and so avoid caffeine's acute pressor effects. In controlled conditions complete caffeine tolerance to intervention doses of 250 mg develops rapidly following several days of caffeine ingestion, nevertheless, complete tolerance is not evident for lower intervention doses. Similarly complete caffeine tolerance to 250 mg intervention doses has been demonstrated in habitual coffee and tea drinkers' but for lower intervention doses complete tolerance is not evident. This study investigated a group of habitual caffeine users following their self-determined consumption pattern involving two to six servings daily. Cardiovascular responses following the ingestion of low to moderate amounts caffeine (67, 133 and 200 mg) were compared with placebo in a double-blind, randomised design without caffeine abstinence. Pre-intervention and post-intervention (30 and 60 min) 90 s continuous cardiovascular recordings were obtained with the Finometer in both the supine and upright postures. Participants were 12 healthy habitual coffee and tea drinkers (10 female, mean age 36). Doses of 67 and 133 mg increased systolic pressure in both postures while in the upright posture diastolic pressure and aortic impedance increased while arterial compliance decreased. These vascular changes were larger upright than supine for 133 mg caffeine. Additionally 67 mg caffeine increased dp/dt and indexed peripheral resistance in the upright posture. For 200 mg caffeine there was complete caffeine tolerance. Cardiovascular responses to caffeine appear to be associated with the size of the intervention dose. Habitual tea and coffee drinking does not generate complete tolerance to caffeine as has been previously suggested. Both the type and the extent of caffeine induced cardiovascular changes were influenced by posture.

The Finometer can function as a standalone instrument in blood pressure variability studies and does not require support equipment to determine breathing frequency.

OBJECTIVE: The Finometer records the beat-to-beat finger pulse contour and has been recommended for research studies assessing short-term changes of blood pressure and its variability. Variability measured in the frequency domain using spectral analysis requires the impact of breathing be restricted to high frequency spectra (>0.15 Hz) so that the data from participants need to be excluded when the breathing impact occurs in the low frequency spectra (0.04-0.15 Hz). This study tested whether breathing frequency can be estimated from standard Finometer recordings using either stroke volume oscillation frequency or spectral stroke volume variability maximum scores. METHODS: Twenty-two healthy volunteers were tested for 270 s in the supine and upright positions. Finometer recorded the finger pulse contour and a respiratory transducer recorded breathing. Stoke volume oscillation frequency was calculated manually whereas the stroke volume spectral maximums were obtained using the software Cardiovascular Parameter Analysis. These estimates were compared with the breathing frequency using the Bland-Altman procedures. RESULTS: Stroke volume oscillation frequency estimated breathing frequency to less than +/-10% and 95% levels of agreement in both supine (-7.7 to 7.0%) and upright (-6.7 to 5.4%) postures. Stroke volume variability maximum scores did not accurately estimate breathing frequency. CONCLUSION: Breathing frequency can be accurately derived from standard Finometer recordings using stroke volume oscillations for healthy individuals in both supine and upright postures. The Finometer can function as a standalone instrument in blood pressure variability studies and does not require support equipment to determine the breathing frequency.