Gymnastik- och idrottshögskolan, GIH

BACKGROUND: Green leafy vegetables (GLV) contain inorganic nitrate, an anion with potential prebiotic effects on the oral microbiome. However, it remains unclear whether GLV and pharmacological supplementation [potassium nitrate (PN)] with a nitrate salt induce similar effects on the oral microbiome.

OBJECTIVES: This study aimed to compare the effect of GLV with PN supplementation on the oral microbiome composition and salivary biomarkers in individuals with high blood pressure.

METHODS: Seventy individuals were randomly allocated to 3 different groups to follow a 5-wk dietary intervention. Group 1 consumed 300 mg/d of nitrate in form of GLV. Group 2 consumed pills with 300 mg/d of PN and low-nitrate vegetables. Group 3 consumed pills with potassium chloride (placebo: PLAC) and low-nitrate vegetables. The oral microbiome composition and salivary biomarkers of oral health were analyzed before and after the dietary intervention.

RESULTS: The GLV and PN groups showed similar microbial changes, probably nitrate-dependent, including an increase in the abundance of Neisseria, Capnocytophaga, Campylobacter species, and a decrease in Veillonella, Megasphaera, Actinomyces, and Eubacterium species after the treatment. Increased abundance of Rothia species, and reduced abundance of Streptococcus, Prevotella, Actinomyces, and Mogibacterium species were observed in the GLV group, which could be nitrate-independent. GLV and PN treatments increased salivary pH, but only GLV treatment showed an increase in the salivary buffering capacity and a reduction of lactate.

CONCLUSION: The combination of nitrate-dependent and nitrate-independent microbial changes in the GLV group has a stronger effect to potentially improve oral health biomarkers compared with PN.

Syfte och frågeställning

Syftet med denna studie var att studera hur olika nivåer av fysisk aktivitet och maximal syreupptagning (VO2max) förhåller sig till olika riskfaktorer för förtida död i hjärt-kärlsjukdom (CVD). Därutöver var syftet att, om möjligt, utifrån erhållna resultat sammanställa rekommendationer för fysisk aktivitet och VO2max för att erhålla reducerad risk för de studerade riskfaktorerna för CVD.

Är det VO2max-värdet i sig, som både kan vara genetiskt-, tränings- och sjukdomsbetingat, eller är det den fysiska aktiviteten bakom ett visst VO2max-värde som är av större betydelse för olika riskfaktorer för CVD?

Metod

Studien baserades på 1851 svenska kvinnor och män i åldrarna 20-65 år utvalda från ett redan insamlat datamaterial från tre tidigare vetenskapliga studier; LIV90, LIV2000 och Vasaloppsstudien. Den fysiska aktiviteten bestämdes genom en enkätfråga i respektive studie och delades in i tre nivåer. VO2max beräknades via ett submaximalt cykeltest eller mättes via ett maximalt löptest. Tolv välkända riskfaktorer för CVD erhölls utifrån enkätsvar eller medicinska testresultat. För analys av den fysiska aktivitetens och VO2max betydelse för varje riskfaktor, gjordes en binär regressionsanalys med kontroll för fysisk aktivitetsgrad, VO2max samt olika kontrollvariabler. Vid varje analys erhölls en oddskvot med 95 % konfidensintervall som beskrev hur risken att erhålla respektive riskfaktor varierade mellan de olika fysiska aktivitetsgrupperna då VO2max hölls konstant.

Resultat

Huvudresultaten i denna studie visade att VO2max hade ett starkare samband än fysisk aktivitet med minskad risk för utfall av enskilda riskfaktorer för CVD. Däremot hade en hög fysisk aktivitetsgrad, motsvarande en belastning som bibehöll/ökade VO2max, liknande betydelse som VO2max för reducering av den generella risken för riskfaktorer för CVD. Fysisk aktivitet på lägre belastningsnivåer uppvisade inte samma signifikanta resultat.

Slutsats

Både högre nivåer av fysisk aktivitet och ett högre värde på VO2max har betydelse för reducerad risk för de studerade riskfaktorerna för CVD och i förlängningen utfall av sjukdom i främst CVD. Därför bör hänsyn tas till båda variablerna då hälsopreventiva och hälsopromotiva rekommendationer utformas.

The peripheral adaptation process associated with repeating eccentric training over a longer period of time was studied in m. vastus lateralis of eleven healthy males aged 24 +/- 4 years. The maximal dynamic concentric muscle strength was only slightly improved after 8 weeks of training. However, eccentric work capacity was dramatically increased (375%). A maximal eccentric stint immediately after fulfilled 8 weeks of training caused a selective glycogen depletion from the type 28 fibers. An increased number of type 2C fibers was observed. The ultrastructure analysis showed an essentially well-preserved fine structure. Volume density of mitochondria was somewhat higher in all fiber types after training. Z-band widths were not affected by eccentric training. It is concluded that skeletal musculature adapts itself in a functional manner to the extreme tension demands put on them. Improved coordination and reorganization of the contractile apparatus of muscle fibers are the determining mechanisms of this adaptation.

The purpose of this study was to investigate the hypothesis that cycling efficiency in vivo is related to mitochondrial efficiency measured in vitro and to investigate the effect of training status on these parameters. Nine endurance trained and nine untrained male subjects ( , respectively) completed an incremental submaximal efficiency test for determination of cycling efficiency (gross efficiency, work efficiency (WE) and delta efficiency). Muscle biopsies were taken from m. vastus lateralis and analysed for mitochondrial respiration, mitochondrial efficiency (MEff; i.e. P/O ratio), UCP3 protein content and fibre type composition (% MHC I). MEff was determined in isolated mitochondria during maximal (state 3) and submaximal (constant rate of ADP infusion) rates of respiration with pyruvate. The rates of mitochondrial respiration and oxidative phosphorylation per muscle mass were about 40% higher in trained subjects but were not different when expressed per unit citrate synthase (CS) activity (a marker of mitochondrial density). Training status had no influence on WE (trained 28.0 +/- 0.5, untrained 27.7 +/- 0.8%, N.S.). Muscle UCP3 was 52% higher in untrained subjects, when expressed per muscle mass (P < 0.05 versus trained). WE was inversely correlated to UCP3 (r=-0.57, P < 0.05) and positively correlated to percentage MHC I (r= 0.58, P < 0.05). MEff was lower (P < 0.05) at submaximal respiration rates (2.39 +/- 0.01 at 50% ) than at state 3 (2.48 +/- 0.01) but was neither influenced by training status nor correlated to cycling efficiency. In conclusion cycling efficiency was not influenced by training status and not correlated to MEff, but was related to type I fibres and inversely related to UCP3. The inverse correlation between WE and UCP3 indicates that extrinsic factors may influence UCP3 activity and thus MEff in vivo.

Aim: To investigate the hypothesis that mitochondrial efficiency (i.e. P/O ratio) is higher in type I than in type II fibres during submaximal rates of respiration.

Methods: Mitochondria were isolated from rat soleus and extensor digitorum longus (EDL) muscles, representing type I and type II fibres, respectively. Mitochondrial efficiency (P/O ratio) was determined with pyruvate (Pyr) or palmitoyl-L-carnitine (PC) during submaximal (constant rate of ADP infusion) and maximal (Vmax, state 3) rates of respiration and fitted to monoexponential functions.

Results: There was no difference in Vmax between PC and Pyr in soleus but in EDL Vmax with PC was only 58% of that with Pyr. The activity of 3-hydroxyacyl-CoA dehydrogenase (HAD) was 3-fold higher in soleus than in EDL. P/O ratio at Vmax was 8-9% lower with PC (2.33±0.02 (soleus) and 2.30±0.02 (EDL)) than with Pyr (2.52±0.03 (soleus) and 2.54±0.03 (EDL)) but not different between the two muscles (P>0.05). P/O ratio was low at low rates of respiration and increased exponentially when the rate of respiration increased. The asymptotes of the curves were similar to P/O ratio at Vmax. P/O ratio at submaximal respirations was not different between soleus and EDL neither with Pyr nor with PC.

Conclusion: Mitochondrial efficiency, as determined in vitro, was not significantly different in the two fibre types neither at Vmax nor at submaximal rates of respiration. The low Vmax for PC oxidation in EDL may relate to low activity of β-oxidation.