INTRODUCTION:
The exact mechanism and the immediate triggers for acute heart attack and brain attacks are not known. Clinical manifestations of these attacks also do not occur at random times but according to a time structure. It is possible that certain external activities, known as triggers, play a major role in the occurrence of these attacks. In one study, half of all heart attack patients reported a temporal relationship between characteristic activities and occurrence of the attack. Emotional stress, sleep deprivation ,large meals, mild and heavy physical exertion were the most frequently reported triggering factors of heart attacks.In the TRIMM STUDY, 76% of all heart attack patients reported an unusual event, shortly before the onset of attack. There appears to be a powerful evidence of a link between these triggers and the sequences of cellular and pathophysiological events that are postulated as being responsible for poor supply of blood in the heart. The morning increase in platelet aggregability is a most frequent trigger of heart attack, which may be the result of increased secretion of cortisol, aldosterone, catecholamines, angiotensin and decreased vagal tone that are known to be enhanced by food and benefited by fasting.[quote]subjects eating low energy diet had low blood pressure,lower glucose,insulin,cholesterol,triglycerides and cytokines:R B Singh, MD[/quote]
Both clinical and biochemical factors may be related to a molecular clock present in the brains suprachiasmatic nucleus . Apart from above triggers, presence of risk factors of low heart rate variability, such as excess fat, more insulin resistant, obesity and pollution may also act by enhancing triggers and trigger-induced brain-related and hormonal mechanisms in the development of poor supply of blood to heart.
Heart attack is a highly dynamic event, which is associated with marked neuroendocrinological dusfunction apart form heart damage. The immediate trigger for heart attack is not known exactly. Studies conducted by Lown, Braunwald, Halberg, Otsuka,Singh,Anna and our group have demonstrated, a marked increase in sympathetic activity, oxidative stress and deficiency of magnesium and potassium during heart attack. Clinical studies have reported an increased incidence of attacks, sudden death and poor blood supply to heart, during first quarter of the day when there is rapid withdrawal of vagal activity and increase in sympathetic tone. In one case control study by Singh etal(Biomed Pharmacother,2004) among 202 patients of heart attack, there was a significant (P<0.02) increase in cardiac events in the second quarter of the day compared to other quarters respectively (16.8%, 41.0%, 13.8%, 28.2%). This characteristic remained common in both men and women and among patients with and without known heart attack (n=52), diabetes (n=53) and hypertension (n=75). Triggers of heart attack were noted among 162(82.2%) of the patients.Brain related and psychological mechanisms were observed as given : emotional stress (45.5%) , sleep deprivation (27.7%), cold climate (29.2%), hot climate (24.7%), large meals (47.5%) and physical exertion (31.2%). These triggering factors are known to enhance sympathetic activity and decrease vagal tone, resulting into increased secretion of plasma cortisol, noradrenaline, aldosterone, angiotension converting enzyme, interleukin-1,2,6,18 and tumor necrosis factor-alpha, that are pro-inflammatory. There is also a deficinency in the serum levels of vitamin A,E,C,coenzyme Q and magnesium, potassium, melatonin, interleukin-10 (anti-inflammatory). In our study, we found a decrease in magnesium, potassium, vitamin A,E,C and beta carotine and and increase in TBARS, MDA and diene conjugates, TNF-alpha and IL-6 which are indictors of oxidative damage and pro-inflammatory respectively.
Table 1. Neuropsychiatric risk factors of acute myocardial infarction.
|
Precursors |
Healthy Subjects (n-595) |
Heart attack (n=202) |
|
Anxiety |
88(14.8) |
122(60.4)* |
|
Depression |
42(7.0) |
45(22.3)* |
|
Type A behaviour |
103(17.3) |
95(47.2)* |
|
Emotional stress |
147(24.2) |
92(45.5)* |
|
Sleep deprivation |
42(7.0) |
56(27.7)* |
|
Cold Climate |
- |
59(29.2)* |
|
Hot climate (>40 degree celcius) |
- |
50(24.7)* |
|
Large Meals |
147(24.7) |
96(47.5)* |
|
Physical Exertion |
173(29.1) |
63(31.2)* |
|
Diabetes mellitus |
70(11.7) |
53(26.2)* |
In another study, by Singh et al (Biomed Pharmacother,2004) among 54 patients with heart attack, that were included in this study, 41 patients had full heart attack, 5 patients possible 2nd stage, 8cases first stage. The control subjects (n=85) were randomly selected from the population of the city of Moradabad drawn from a similar aqe range of subjects after exclusion of heart attack (n=9), diabetes(n=6) and excess intake of trans fatty acids (n=20). Mean lipopotein(a), total cholesterol and triqlycerides were significantly higher and mean nitrite level,lower in the heart attack group, compared to control group.There was a significant greater incidence of heart attack events in the second quarter of the day (6.00AM to 12.00noon) compared to 3rd quarter. Lp(a), triglycerides, blood glucose, plasma insulin,malondialdehyde,diene conjugates,TBARS and TNF-alpha and IL-6 which were significantly greater during acute phase,showed a significant decline,and serum nitrite and coenzyme Q,an increase, at 4 weeks of follow up, when the acute reactions evoked by heart attack, were controlled.Large breakfast was a predisposing factor of heart events in the second quarter of the day and it was significantly associated with metabolic reactions.The findings indicate that acute reactions as a result or as circadian rhythms appear to be important in the pathogenesis of complications in heart attack and that a large breakfast in association with nitrite deficiency, may further trigger the circadian rhythms.However more studies in a large number of subjects would be necessary to confirm our findings.
We observed a significant higher incidence of cardiac events in the second and fourth quarters of the day which is similar to other studies published from Europe and United States and other parts of India .It is known that second quarter of the day is associated with decreased melatonin release at awakening due to sunlight, and increased release of catecholamines,cortisol and serotonin.There is increased platelet aggregation(stickyness of blood), as a trigger of heart attack which may be the result of greater concentration of catecholamines and cortisol in the blood and due to large fatty meals.There was a deficiency of coenzyme Q10 and nitrite in heart attack patients indicating their increased requirement to fight the stress.
There is little information on the role of nutrition in the onset of acute reactions and heart attack.We observed that subjects consuming large breakfast and meals especially dinner were more common victims of attacks, compared to apparently healthy subjects of same age and sex.Higher vegetable ghee intake was also more common among heart attack group(Table 2).It is known that different types of fatty acids and refined carbohydrates in the diet influence different physiologically relevant mechanisms,especially those concerned with haemostasis and inflammation in the body.As the role of various factors,influencing clot formation in the heart artery and thrombolysis on risk of heart and stroke are more firmly established,our knowledge concerning the effects of different types of nutrients on these factors remains limited.A recent study, showed that postprandial leptin response was lower after a carbohydrate meal in obese women,than in lean controls,suggesting an impairment of such response of leptin regulation due to obesity.It is known that postprandial leptin changes are higher after carbohydrate meal than after a fat meal similar to insulin changes.
We found that consumption of a large breakfast was associated with greater proinflammatory cytokines;TNF-alpha and IL-6,than in subjects consuming low energy breakfast(Table 3).Increased levels of TNF-alpha and IL-6 have been observed in patients with obesity,type 2 diabetes,insulin resistance,glucose intolerance,hypertriglyceridemia,hyperleptinemia and heart attack, which could be greater in patients with attacks.There is no previous evidence that people consuming large breakfast have greater proinflammatory cytokines,as observed in our study.There is potential evidence,however,that heart attack may be associated with greater levels of proinflammatory cytokines due to metabolic reactions such as catecholamines,cortisol,serotonin,hyperinsulinemia,hypertriglyceridemia and hyperglycemia that are common in patients with attacks.It is possible that people consuming large,fatty breakfast enhance the release of catecholamines,glucose,insulin,triglycerides which may have an adverse effects on cardiovascular function.
Experiments in animals indicate that ventromedial hypothalamic(VMH) lesion in the brain, in rats induces hyperphagia,and excessive weight gain,fasting hyperglycemia,hyperinsulinemia,hypertriglyceridemia and glucose intolerance There may be suppressed splenic natural killer cell activity,when the animals are hyperphagic and obese.There is increased release of interferon-alpha,IL-1,IL-2 and TNF in response to noninflammatory and inflammatory stresses.Longterm infusion of norepinephrine plus serotonin into the VMH part of brain, impaired pancreatic islet cell function in as much as these abnormalities are observed in insulin resistant animals by several researchers.It is possible,that heart attack is associated with high level of psychological and hormonal stress,which may have caused the release of proinflammatory cytokines which can damage heart and endothelial cells resulting into increased susceptibility to clot formation and heart attack and heart failure.
ADVERSE EFFECTS OF DIET:
Dietary fat composition can also influence platelet function and platelet aggregation and blood clotting.Experimental studies indicate that dietary butter or coconut,increase the sensitivity of platelets to aggregation and clot formation and enhances the release of harful catecholamines.Hypercholesterolemia is known to be associated with an increased sensitivity of platelets to aggregating agents.A large breakfast rich in fat may enhance platelet aggregation and clotting resulting into heart attack, as noted in our study.Reduction in the saturated fat in the diet may decrease,platelet aggregation and catecholamines resulting into decrease in blood pressure and heart rate.A diet rich in n-3 fatty acids may decrease cytokines.
Table 2: Clinical characteristics of subjects:
|
|
Acute myocardial infarction (n=54) |
Controls (n=85) |
|
Sex- males |
45 (83.3) |
76(89.4) |
|
Mean age (years) |
49.5+ 4.2 |
52.1+ 5.2 |
|
Body mass index (kg/m2) |
23.7+ 3.2 |
22.4+3.4 |
|
Hypertension (>140/90 mmhg) |
25(46.3)* |
25(29.4) |
|
Glucose intolerance |
12(22.2)* |
10(11.8) |
|
Diabetes mellitus |
14(25.9) |
-- |
|
Smoking |
24(44.4)* |
28(32.9) |
|
Higher transfattyacids (>5g/day) Large meals(>1000 Kcal) Large breakfast(>1000 Kcal) |
27(50.0)** 27(50.0)** 22(40.7)** |
-- 25(29.4) 10(11.8)
|
Table 3 :Risk factors in relation to breakfast and dinner.
Data Large breakfast,n=22) Small breakfast,n=32)
|
|
Baseline |
After4 weeks |
Baseline After 4 weeks |
|
|
Lipoprotein(a)mg/dl |
23.1+5.4 |
20.1+4.2* |
22.5+4.6 19.7+4.1* |
|
|
Triglycerides (mmol/L) |
1.88+0.61 |
1.70+0.38* |
1.81+0.60 1.64+0.32* |
|
|
Blood glucose (mmol/l) Plasma insulin(mg/dl) TBARS(pmol/l) Malondialdehyde(pmol/l) Diene conjugate(OD) Coenzyme Q10(ug/ml)
Interleukin-6(pg/ml) TNF-alpha(ug/dl) |
7.7+1.6
47.5+11.3 1.87+0.46 2.68+0.34
27.5+4.2 0.21+0.02
32.6+6.2 42.5+12.8 |
6.0+1.2*
36.3+5.6** 1.32+0.33* 2.02+0.21*
24.6+4.0* 0.32+0.23*
22.5+4.3* 23.6+4.1* |
6.6+1.4* 5.5+0.30*
43.2+8.8* 27.6+3.5* 1.77+0.42 1.30+0.31* 2.66+0.33 2.01+0.21*
26.2+4.1 24.2+3.5* 0.23+0.03 0.45+0.24*
27.5+5.2* 20.6+0.22* 38.2+10.6* 19.6+0.18* |
|
ROLE OF FASTING OR LOW ENERGY DIET:
We have found that subjects eating low energy diet had low blood pressure,lower glucose,insulin,cholesterol,triglycerides and cytokines.In 32 subjects,on no breakfast,fruits and vegetables in the lunch and normal dinner,we observed a very low blood pressure variability compared to subjects eating normal meals.It is possible that no breakfast or small amount of breakfast containing protective foods such as almonds,walnuts and black raisins,may have a beneficial effect on the harmful body chemistry that occurs during the 2nd and 4th quarters of the day.It is suggested that take small breakfast and dinner and normal lunch and supper to avoid the adverse effects of foods during circadian rhythms of our body and prevention of heart attacks.
R B Singh,MD
Professor of Medicine,Halberg HospitalCivil Lines,Moradabad-10(UP)244001 ,India
Reproduced with permission
Discuss this here