How much food is too much? threshold doses for allergenic foods

This review summarizes recent findings and controversies in the area of threshold doses for allergenic foods. Over the years, there have been many clinical reports that ingestion of small amounts of food can elicit IgE-mediated allergic reactions. In exquisitely allergic individuals, the threshold dose for elicitation of such reactions is often considered to be zero. However, some food-allergic patients report that they can tolerate small quantities of allergenic food. Are very low quantities hazardous to foodallergic consumers? How much of the offending food is too much? Why is the concept of a threshold level important? There have been very few studies to date on threshold doses for allergenic foods, and more research is needed in this important area.     

Multiple renin-angiotensin-aldosterone-blocking agents in heart failure: How much is too much?

Angiotensin-converting enzyme inhibitors (ACE-Is) and β-adrenergic receptor blockers (BBs) have been effective in reducing cardiovascular morbidity and mortality in patients with heart failure (HF) and left ventricular systolic dysfunction (LVSD). Angiotensin receptor blockers and aldosterone blockers have also been shown to be effective. Although ACE-Is and BBs remain the therapies of choice for patients with HF-LVSD, many clinicians have attempted to further reduce patient morbidity and mortality by adding another inhibitor or blocker of the renin-angiotensin-aldosterone system to an ACE-I or BB. This article reviews the efficacy and safety of adding another renin-angiotensin-aldosterone system inhibitor or blocker to an ACE-I or an angiotensin receptor blocker plus a BB in patients with HF-LVSD.     

Iron: how much is too much?

Gross iron overload has long been known to result in diabetes mellitus. However, it is now thought that milder levels of iron overload, possibly within the normal range, also increase the risk of diabetes mellitus. The article by Rawal et al in this issue (Diabetologia doi:  10.1007/s00125-016-4149-3) provides further support for the relationship between mild degrees of iron overload and the risk of gestational diabetes. The purpose of this commentary is to briefly discuss the background of this relationship and the implications it may have for routine pregnancy care.     

How much blood is needed?

Demographic changes in developed countries as their populations age lead to a steady increase in the consumption of standard blood components. Complex therapeutic procedures like haematopoietic stem cell transplantation, cardiovascular surgery and solid organ transplantation are options for an increasing proportion of older patients nowadays. This trend is likely to continue in coming years. On the other hand, novel aspects in transplant regimens, therapies for malignant diseases, surgical procedures and perioperative patient management have led to a moderate decrease in blood product consumption per individual procedure. The ageing of populations in developed countries, intra-society changes in the attitude towards blood donation as an important altruistic behaviour and the overall alterations in our societies will lead to a decline in regular blood donations over the next decades in many developed countries. Artificial blood substitutes or in vitro stem cell-derived blood components might also become alternatives in the future. However, such substitutes are still in early stages of development and will therefore probably not alleviate this problem within the next few years. Taken together, a declining donation rate and an increase in the consumption of blood components require novel approaches on both sides of the blood supply chain. Different blood donor groups require specific approaches and, for example, inactive or deferred donors must be re-activated. Optimal use of blood components requires even more attention.     

Renal failure and ACE inhibition: how much is too much?

Summary The dose-response relationship between pharmacological blockade of the renin-angiotensin system (RAS) and angiotensin II concentration in the circulation, on the one hand, and decrease of blood pressure, on the other hand, has been well established. In contrast it is currently unclear which dose of ACE inhibitors and/or angiotensin receptor blockers is optimal for nephroprotection. Clinical studies are rendered quite complex by an early decrease of glomerular filtration after RAS blockade and by side effects at higher doses such as renal sodium loss, hyperkalemia, anemia, etc. Animal experiments and recent clinical studies suggest that the doses of ACE inhibitors or angiotensin receptor blockers required for maximal reduction of proteinuria (as a surrogate marker) and for optimal nephroprotection (retardation of the loss of glomerular filtration) exceed those required for maximal lowering of blood pressure. Ongoing studies try to define the relative merits of high dose monotherapy (ACE inhibitors or angiotensin receptor blockers) versus a combination therapy of the two.